long nights

My son has always been pretty good about waking once eatting and going back to sleep... well tonight he has been up for 2 hours he is fed changed and is just screaming when I put him in his crib I let him cry to see if he would fall asleep I Torres at least 5 times my boyfriend tried twice he gets sleeping than we put him in the crib and he wakes up screaming.. I am now on the couch and he is in his swing quiet why is he doing this? Never had a problem going back to sleep before I though maybe he was in pain but now that he is quiet in his swing maybe not idk... ideas?