Hello, to both of you,

irundawg
Yes, many have had the "heart attack " scare - & even gone to ER to be checked just to be sure.

I has a similar episode during the time I was having severe upper body spasms. (felt very locked up in the upper body)
Usually it's the inter-coastal muscles spasming that tightens up the whole rib cage /chest and makes it feel like a heart attack.
But if you have any heart risk factors or family w/ heart issues it is good to get it verified before assuming it it TOS or spasms related.

If you know of any expert physical therapists, bodyworkers or chiropractors they may be able to evaluate the muscles to decide if it is indeed spasms and if so there are modalities to help reduce those.

My chiropractor was the one to help me the most during the worst times.
But I feel he is more of a healer than a regular chiro, he uses many therapeutic modalities like low level laser, ultra sound, nimmo, IF stim along with adjustment as needed.
I also had great help from an advanced PT - he taught PT as well as having his own therapy clinic.

And I suppose MDs will rx muscle relaxers after they make sure it isn't a heart issue. But meds usually won't fix the problem all alone - you also need to figure out & address what caused or how the spasms occurred.

We have quite a few recent threads with various self help ideas being talked about.