You’re not the only one with that feeling! I had a single mastectomy Jan 2025 then DIEP Double August 2025 and after that 2nd surgery the breast surgeon & plastic surgeon explained where they’ve attached the tissue to the breast wall is where I feel the pulling sensation. As the nerve feelings come back, it’s actually getting more annoying/ uncomfortable - like you, I can’t lie on that side. When I do a revision later in year to clean up my incisions, the plastic surgeon says he will “snip” that a little to see if it improves the discomfort.
Not sure if we have the same root cause but definitely the same side effect (if you’ll pardon the pun)