Popped a bumb on my lower back now its bigger and it hurts to touch and lay certain ways, what should i do ?

Don't know exact location on your back, but could be an abscess or even an infected pilonidal cyst. This is not something you can ignore, as it is likely an infection that needs to be drained properly. See your PCP or use Urgent Care Center today or tomorrow. In meantime, hot compresses to area may promote it to start draining on its own and relieve some of the pressure/pain.