Wondering what is causing my lung pain. Background: Worsens both with activity/movement, and whilst lying down. Sitting still provides relief. Seems related to my menstrual cycle - over past year it is worst either during, or just before, menstruation. I ve been checked for heart issues - tests came up clear. Also had CT for chest to check for clots, came up clear. I have existing conditions: recurring stage 4 endometriosis in bowel and reproductive organs, PCOS and ongoing joint pain.