Suggest Treatment For Pain Under The Right Breasts

I have pain under right breast on my ribs. I can not wear a bra. The pain is a dull pain like I am wearing a belt around me. I am 5 4 weigh 165. I had a mammogram about six months ago, ekg, blood work and chest x-ray. I was injured on my ribs about 20 years ago but they seemed to heal fine. The pain will come and go. It has done this for years, but within the last six months has bothered me more. I am 65 years old and babysit my year old grandson who weighs 31 pounds. I do not take any medications and no surgeries.