I Have Pain In The Ribs That Comes And Goes.

I have pain in the ribs that comes and goes. I know it could be related to being constipated. What are some other things that could cause it? One doctor a long time ago recommended a test that had to be done in the hospital. One thing that they did was with the "hammer" tapped the bone by the shoulder and it really struck a sore spot. Any ideas what it could be?