Suggest Treatment For Pain In Hte Breast

Every 4 or 5 weeks I have a pain or discomfort in the center of my breast that goes thrugh to my back..it will last about 30 min..go away, come back an hour or two later for 25 or 30 min..this will go on for about 7 or 8 hours and I wont have it again for weeks. I have had EKG..stress test, MRI. Nothing shows anything wrong..I am 73 years old, female. and overweigtht by about 30 pounds.