There was. It's called the Great Migration (1916-1970).
They were poor and it was hard to find work.
In the immediate aftermath of emancipation, the vast majority of slaves were illiterate and owned nothing. More than half of Americans worked on farms at that time, especially in the South, which lagged behind the North in terms of industrialisation. Most freed slaves ended up as farm labourers or sharecroppers (farmers who rent rather than own their land). The Southern economy took decades to recover from the Civil War, and with the end of Reconstruction and the rise of violence-enforced white supremacy helped ensure that many former slaves remained stuck in poverty.
That basic situation didn't really shift until WWI, when the war in Europe slowed European immigration to the US to a trickle, while at the same time strongly increasing the demand for factory labour in Northern cities. That created an opportunity for black people, and they jumped at it. Cities like Chicago, Cleveland, and Philly went from being less than 2% black in 1900 to 20-30% black by 1960. Overall, the black population of Northern states increased by 40% during the period.