Hi I Have Been Experiencing Chest Pain An Sore Arms

Hi I have been experiencing chest pain an sore arms ( biceps and shoulders) for the past 6 weeks. My chest pain is on the left in the vicinity of my heart but it seems not my heart . Chest X-rays ,ecg, and stress test have ruled out heart disease. The muscle pain is worse in the morning - often wakes me up. The chest or "heart" pain is intense when I sneeze or yawn or take a deep breath.
I am generally in good health age 56 female - recent diagnosis of thyroid cancer and wondering if there is a connection?