What could cause chest discomfort, nausea, and pain in the arm, back, and jaws in a 31-year-old?

Hello doctor,

I am 31 years old. My issue is that sometimes after meals when I lie down for sleeping (for a nap in the afternoon) after some time when I start to feel sleepy, I get chest discomfort (not heartburn), nausea type feeling, pain in my left arm and back and also pain in jaws (I feel as blood is not reaching these areas). This is causing serious concern for me as to why this is happening. It often prevents me from sleeping due to fear of any heart condition and causes anxiety. This condition disappears when I usually do some physical activity like walking. As far as my history is concerned, I had gone through ETT (exercise stress test), echo, ECG, and CT angio two years ago and all came clear. I also had my blood tests which all were clear except for some high uric acid and low B12. I have had hypertension for the last four years and started taking medicine one year ago (5 mg Byscard in the morning and 8 mg Advant in the night). Furthermore, the doctor told me that I have anxiety. I also have gastric issues like, heartburn, bloating which may be a cause of chest discomfort after meals but the pain in the left arm, back, and jaws which come while going to sleep and go away during physical activity is a cause of concern. Please suggest.

Thank you.