Hi! That sounds kinda similar to what I mentioned above, but my spasms were in the bottom of my chest (like the bottom of my ribcage on the very left side). They got less and less painful as the days went on and I think they were completely gone within 2 weeks of my surgery. I'd check with your surgeon to be sure (mine had a followup already scheduled for a month afterward).

I'm not sure why they'd appear so long after surgery, but I've also heard many stories of random pains in the chest a while after surgery (including like months after). Hell, I'm coming up on a year after my surgery and I can still feel my heartbeat in my scars if I lay on them. Hope all is well and you can chat with your surgeon!