Did North Korea have political prison camps from the start or did they form later and what led to their creation?

Two parts to your question, so that's how we'll divide the answer! Well, "answer" might be stretching it; the best we can really do is give you an educated guess.

Part #1: Did North Korea have political prison camps from the start or did they form later? The first of North Korea's prison camps probably dates to the late 1950s. To put this in context, this was in the post-Korean War period (1950-1953) while Kim il-Sung was powering through the last of his political opposition, consolidating power, and creating or formalizing a number of features that later came to define North Korean society (e.g., the songbun system, agricultural quotas, and the public distribution system, among others). So no, they weren't part of North Korea's "start," although it's very probable that NK's prison system made use of infrastructure left over from the Japanese occupation. However, we don't know exactly when the camps were built, staffed, or filled. The first occupants are obviously in no condition to talk, and barring some truly extraordinary circumstances, the Kim regime is very unlikely to discuss their history publicly.

We think the system was up and running in the late 1950s because that's around the time that North Korea's dissidents mysteriously stopped being forced into exile. Kim didn't have the luxury of uncontested rule at first. He was the equivalent of a high school dropout and just 33 when World War II ended. He'd been out of Korea itself for almost two decades and didn't even speak the language all that well after spending so many years in China. However, the Soviets saw the value of putting a former Korean freedom fighter in charge, and a lot of Soviet-Koreans (who formed a major part of the nascent North Korean government) were more or less content to accept him. They certainly didn't see him as the most qualified person to run the country, but he was a useful figurehead and a means of giving the North Korean state more credibility than its South Korean counterpart. South Korea's government was largely staffed by people who'd collaborated with the Japanese imperial government, so this was a major propaganda victory for the Soviets. (Although the reality was that Japanese collaborators were also a significant part of NK's government.) For a hyper-nationalist state still smarting from decades of occupation, that was an easy way to attract popular support.

However, the Soviet-Koreans were among the most vulnerable people once Kim had established himself more firmly in power. Most of them weren't huge fans of him, and many knew things that were extremely damaging to the image he was trying to build. Incidentally, this is also where the question over Part 2: What led to the camps' creation? starts to get addressed:

They knew that the "great hero of the revolution" barely spoke Korean when he returned to the country.
They knew he'd been an officer in a Chinese-led army fighting in Manchuria and that he'd never fought in Korea at all.
They knew he was a very small part of a very large struggle. He was important enough for the Japanese to have put a price on his head, but not important enough to have been the focus of major efforts.
They knew the degree to which he'd been coached on how to speak and act while he was drumming up support for the Soviet-overseen government.

Many of them were much better-educated than Kim in addition to being bi- or trilingual (Korean/Russian/Chinese) and could become serious threats to his power. This was a big problem for Kim to overcome, and you really see the beginning of NK's totalitarian police state in the years following the Korean War. Most of the Soviet-Korean population was forcibly exiled -- typically back to Russia -- and the North Korean state washed its hands of them. Their properties were seized, they were denounced as spies and counterrevolutionaries, entire families were kicked out of the country, and they were written out of North Korea's official state histories.

Problem solved, right?

Not quite. Khrushchev was a huge thorn in Kim's side too. Nikita Khrushchev became the First Secretary (i.e., head honcho) of the Soviet Communist Party shortly after the Korean War "ended" in 1953. Khrushchev was widely despised in the West for the crushing of the Hungarian uprising and the "We will bury you" incident; most Westerners saw him as an emblem of aggressively expansionist and belligerent communism. 1956-1963ish was arguably the height of the Cold War, and those were scary, scary days. However, within Soviet circles Khrushchev was serious about reforming the U.S.S.R. and its client states away from the cruelties and inefficiencies of Stalinism. For states like North Korea, which were about as Stalinist as you could get without actually being Stalin, this was a huge diplomatic and political problem. Equally frustrating is that exiling the Soviet-Koreans back to Russia just delivered a bunch of people who hated Kim to a powerful state that was now willing to listen to their concerns. Still worse is that the U.S.S.R. was NK's main financial sponsor.

So Kim needed another place to dump the biggest threat to his authority. If you're Kim in the mid- the late-1950s, you're thinking: "Shit. Where do I put these people?"

The U.S.S.R.: Too politically sensitive. NK was and remained financially dependent on the Soviets, and he didn't want to attract any more of Khrushchev's attention than he already had. As it was, the North Koreans took full advantage of the Sino-Soviet split, which started in the early 1960s.
South Korea: Fat chance. There really wasn't a mechanism to send people to the south anyway, and it would have been an enormous propaganda victory for the South Korean government. Boo on that.
China: He could have sent them here -- there's a significant Korean-speaking minority in northeastern China -- but he had no control over what they'd do, where they'd go, or who they'd talk to once they got there.

Exile for dissidents, political opposition, or anyone he thought might become a threat was rapidly becoming an unattractive choice. The logical but equal-parts vicious and tragic choice was to imprison them and their families forever. People who became his prisoners would never pass outside of his control: They would never taste freedom again: They would never be a threat. He could even use them and their families as free labor for the country until they died. The only leniency afforded by the system was the release of a family once the original offender was dead, but they would be branded former prisoners, never allowed to live in a prestigious or important city, and never allowed to occupy a sensitive job.

So our best guess is that the North Korean camp system became active between 1956 and 1960, and that it started mostly as a way to neutralize the Soviet-Koreans. Khrushchev really went public with the campaign to reform the Soviet/client economic model in 1956. The flow of Soviet-Koreans exiled to the U.S.S.R. slowed significantly by 1960, and the most plausible reason for it is that they were being arrested and sent to the early camp system instead. It didn't take long for the camps to expand and accommodate basically anyone that Kim saw as a potential threat, which is how people like Kang Chol-hwan (the author of The Aquariums of Pyongyang) ended up in Yodok for 10 years. His crime was being the grandson of a person who'd opposed Han Duk-su, who was Kim's pick to lead the NK-affiliated Japanese-Korean association. As incredible and horrifying as it sounds, people died in the camps for reasons far flimsier than that.

Unfortunately, we don't have a perfect or perhaps even totally accurate answer for your question given how murky North Korean history is, but this is the narrative that historians believe makes the most sense given the events we can confirm.