I have had chest pains for over a year. I had CAT scans MRI's. What could be the cause of the pain.?

Also I have had pain underneath left breast and sometines shortness of breath.

Nick some of the pains can be caused by stress, as a matter of fact stress is becoming, if not already the biggest risk of heart disease. Has your doctors done the related blood tests for stress and also indigestion? Pain like you are describing should be taken very seriously and you should go to a cardiologist and/or pulmonary specialists. Good luck! Please keep us informed cause it could help others with the same symptoms. You should at least get three different doctors opinions. This is your health and doctors who care will see that you get the follow up care that is needed. This is your body and you know above all else what is normal for the way you are feeling and don't let a textbook doctor try to diagnosis you. We are all different and don't fall into the regular category of a book.

the cause of your pain may be a stupid doctor. find a new doctor

Have you had a stress test?

I hope you find out, because my husband is going through the exact same thing, right down to the pain (or what he calls fluttering) under the breast.
If you find out, could you let us know what it is?

Good Luck and I hope you feel better soon.

It could simply be from stress. Start monitoring when you have the chest pain, see if there was a very stressful time before the chest pain. My boyfriend gets these from stress.

Good luck

Do you have diabetes? Has your blood glucose been checked when having the pains? I went through the same thing and and after all the EKGS and stress tests etc. figured out on my own that it was my blood sugar.

Another cause can be anxiety.