Sounds like house shifting at worst and maybe studs flexing from moisture changes at least. Lumps are probably nail pops which means probably pulling the nails, installing screws, retaping, remudding, and repainting.
Cracks above doors if on the corners could be from fiberglass tape on door joints. After it first came out, rockers were using it and now have learned that it isn't as good as paper in places prone to movement cause it shifts and allows the mud to crack. It is also recommended not to have seams at door and window edges but to run the full sheet out and then cut out for doors and windows. Sometimes people save drywall by patching in above doors and windows leaving the seam to crack later when there is a shift. Probably have to retape, remud, and repaint.
Main thing is too find the source of the shifting, a basement or foundation wall shifting (look for cracks and out of level) or one or more floor joists that have weakened or cracked and need bracing. Could also be lumber expanding and contracting from humidity changes. We are having weird weather patterns now. Good luck. Where are these cracks at? load or non load bearing interior walls, exterior walls, above the middle or at the corner of the doors?