Recurring stomach pain, loud gurgling sound from intestine, diarrhea and then subsides. What could be this?

Hello. My son has had on and off severe stomach pain for 2 weeks. The pain comes and goes, but when he gets one of the severe pains where he can't seem to take it, shortly after you can hear a loud gurgling sound coming from his intestines and then the pain seems to subside or he has diarrhea and then is subsides. He was at his Ped. office on thurs and we did bloodwork and came home with a parasite testing kit which I brought back the first test tube friday AM. I have not heard back with any results. Things seem to be getting worse as they are happening more frequently. I should also mention that this is a child that is rarely sick and when he is rarely complains. Aside from this thursday he hasn't been in the dr office since his well child visit a year ago. What should be our next step in figuring out what is going on?