Stress can certainly cause all kinds of strange symptoms and body sensations and I am glad to hear you have had an ECG to double check your heart.
If symptoms persist however, I would recommend that you go back to your GP to discuss this.
Unusual physical sensations can cause further stress and thus create a vicious circle between mind and body.
Your GP should be able to alleviate your physical concerns with further checks if necessary.
You could also try some deep breathing exercises because when we are anxious we tend to breathe with shallow breath which can cause further tension in the body.
Supplementing with Magnesium in the evening can also help relax muscles and can be taken alongside Passiflora Complex which is used traditionally for easing stress and nervous tension.
It takes up to a week to feel the benefits and if you have not noticed an improvement after a month, then we suggest exploring an alternative.
I hope the symptoms ease soon for you.