I'm reeeally trying to lose some weight and bring up my fitness level, but I get terribly painful stitch in my side when I try to jog after about 10 mins.

I eat careully and excercise/warmup for about 1/2 hr to an hour each evening. I allow myself about 45 mins before excersise after eating, and I drink water before I go running. Anybody tell me how to stop the painful stitch??