What Causes A Painful Lump Above The Navel?

I have a knot above my navel, I have pain in the belly button area. I have constant gas and diareaha that over the counter medicine gives temporary relief. I get cramps in the stmqach and buttock area right before I pass gas and have a bowel movement. I have another knot that has formed near my groin area and I have a slight pain right before I urinate. I only have medicare and go the public hospital and they are not in a hurry to get to the diagnosis. A ultrasound was done but they could not see the knot well and recommened a mri but I have pain and wonder if I need to go to the emergency room for immediate treatment