I have pain on the left of my left chest. Doesn't seem to be my breast which looks and feels normal when I examine it. The pain is not sudden or sharp but feels more like background pain behind my breast. It can be stimulated by breathing in or out deeply especially if the breath is forced out and feels on the left side of left breast where it meets the chest wall. I have had muskulosketal problems with my upper back and neck where tendons feel very tight despite exercises and stretches. Physio treatment was very effective in improving matters and I do Pilates and yoga now but some tightness remains around my neck and shoulders. When I pull my shoulder back and forth I feel this chest pain especially if I'm vigorous about it and my shoulder feels slightly stiff after lying on it which is a new symptom. I am female, life long non-smoker, virtually tee-total, 164cm, 70kg, age 51, periods stared to be irregular last summer (2 in 7 months). Being widowed I am not pregnant (no sexual activity). I'm not on any medication and have good exercise tolerance although could be fitter. This particular pain has been around for a few weeks and I couldn't account for it (no heavy lifting or such-like) but I saw an 'advert' about breast cancer saying pain might be the only symptom. Consequently I am pretty worried and thought it could be any other form of cancer too like something on my chest wall. I wouldn't normally look on-line for answers but thought I'd have a look for possible causes and came across this site. I have a GP appointment on Monday.