Welcome @lll3, I can imagine you're concerned. There is something called post-mastectomy pain syndrome (PMPS) because it was first noticed in women who had mastectomies, but it can also happen after other types of breast-conserving surgery (such as a lumpectomy). Read more https://www.cancer.org/treatment/treatments-and-side-effects/physical-side-effects/pain/post-mastectomy-pain-syndrome.html

Did either the surgeon or radiologist suggest going in for an exam? I might ask if a referral to physiotherapy might be recommended.