What Causes Pain And Discomfort In The Chest?

Hi, I m having a stitch like pain in my chest near my heart. My heart feels like it is beating after a run, but I ve been resting all day. It s also causing as shallowing in my breathing. I do have hypotension, thus started in January and sometimes tachycardia however it s not too fast today, sitting at about 88 bpm I ve had clear echo. I m in medications for post Lyme disease, that I have had proven several times with serology from spinal taps. My ID doctor is a microbiologist as well, and has confirmed relapse after 30, 42 days of IV antibiotics. I m not currently in any. I m not anxious, I m sitting here quietly, trying to breath through the pain.