Dealing with Chronic Chest Pains and Feeling Alone

I've been getting chest pains On my left side mostly under my breast the side of my breast and sometimes my actual breast for years I've been to countless doctors, cardiologist, gastrologist, Obgyn's, primary care doctors, & ERs and everyone keeps saying I'm fine I will admit I need to make some lifestyle changes need to quit smoking cigarettes, need to lose a little weight (5ft 4in 172 pounds) but it's all so hard when I'm in constant pain I just turned 25 and I've been dealing with this since I was 16. I also have the worst period cycle ever I literally get my period once every 3-6 months and doctors have yet to do something about this! can anyone relate? Any advice? This makes me feel so alone! Ps recently signed myself up for therapy to see if it's "all in my head"