Breast pain in one breast

Merm

I have been having breast pain in my right breast for several months. It feels bruised and hurts all the time. The intensity of pain changes from bearable to extreme. Some days I can barely walk without feeling discomfort. I stopped breastfeeding around 1.5 years ago, so I doubt it has anything to do with that. My doctor checked me and found nothing. Then I had a mammogram and ultrasound. Still nothing. I’m beyond frustrated. They say it could be hormonal, but it hurts allll the time! Not just during periods or ovulation. Any thoughts? Has anyone experienced this before?