Well your warm side should be a little warmer (around 90 degrees). And ball pythons don't need a UVA bulb. Just a regular heat bulb if you need it to maintain your temps.
Snakes can go for awhile without pooping and sometimes they don't have large poops either. Although if he has eaten 50 times in 2 months that is a lot. You should only feed him once a week (or once every 5 days if he is a baby). Is the area around his tail really swollen and big compared to the rest of his body? If you are really worried then you could try soaking him in a small bowl of warm (not hot!!) water...that often encourages them to go to the bathroom.
If he seems fine though then he probably is. Sometimes they do go awhile without pooping