Please help? Feels like I’m going insane!

31 year old male here (painter and decorator), it all started in December 2025, I overstretched while painting a very high ceiling and I haven’t been the same since. Multiple clear ECGs, numerous amounts of blood tests done and come back fine, troponin levels fine. Doctor diagnosed costochondritis but I can’t stop worrying it’s something else going on as she didn’t even really know what it was. I have pains in my upper chest, both sides just below the collar bone, my neck seems tight most days, left sided jaw pain and pain that radiates down my arm! It’s all too much to cope with, my anxiety is through the roof on a daily basis thinking I’m having a heart attack even though I’ve been cleared numerous times by different doctors/hospitals! Please help 😩