Two things I will suggest to you, 1) costochondritis and 2) gallbladder
I have costochondritis, it is inflammation of the joints between your ribs and your sternum. If you press on certain areas of your chest, you can recreate the pain. This can be relieved with NSAIDS (Ibuprofen, Aleve) and an ice pack or heating pad.
If it's gallbladder, it can be referred pain. Does this pain worsen with certain foods? If you push on the area that hurts can you feel pain else where?
I have costochondritis, bad gallbladder (when I push on my mid chest or right abdomen the pain is felt in my belly button, left and right chest and in my lower stomach), and IBS and I have horrific health anxiety. I literally just got over the heart obsession so I definitely understand where your coming from.