What's going on?

So my son will be 5 months on the 9th, he has been teething a little extra lately and we started introducing him to rice cereal and bananas, he's getting better with them each time. I've noticed his poop is more like clay and he poops only a little. Well the past two nights I have had to give him infant tylenol because he wakes up screaming well I hate giving him medication so I tried tonight without it and a few hours late he's screaming in pain and won't stop. I just gave him tylenol praying he sleeps. What do I do????