Good news but why do I still feel bad

So.... From what I have read, the heart pains I have felt are either Precordial Catch Syndrome or truly and Muscular/Skeletal thing. Almost feels like pinched nerve... It pinches and feels like a stab right in my heart. And my stupid anxiety / panic make it so much worse and make the pains way more intense.  My Primary care doc is awesome... Said it's for sure not my heart and that she will go to the ends of the earth to figure out what it is. Told me yesterday to go home, take a Xanax and relax and that I will be fine. Love her... so very happy to have found her.
I guess this is good news right?  She is running all the test to make sure. I am on my acid reflux meds to see if that helps. I go for the Chest Cat Scan tomorrow to rule out anything with the lung. Both cardios said the symptoms I am having are not from my heart that my heart looks very health.
So, then why when I get a super sharp pain, does it throw me into a panic attack and then the pains keep coming?  why then can't I just accept that they are non harmful and we are working on figuring them out? I don't understand it.... I just want to be able to accept what I am being told and move on with my life but instead I dwell.  I know once I find the answer (which to be honest, there may never be one, we may just rule everything else out) I will be ok but not knowing seems to drive me insane. :(
All of you out there, with your support, you are all amazing, thank you so much... I am so glad to have all of you as friends and have you on this site, it brings me SO much relief xoxoxxo