catch -
I'm not dx'd with anythng, but in Aug I had exactly what you had - (sharp stabbing pains along with a tight band sensation) and ended up in emergency on heart monitors. (When I phoned 'nurse-on-call' they told me call an ambulance!)
I was fine after a few hours and Dr said it was just unexplained 'muscle spasms'.

It's happened only mildy since.
If I have MS I would say it's the 'hug'.