<s>[INST] I am 17 years old, im only 53 and I weigh about 110 pounds. Yesterday I got a terrible pain behind my left breast that hurts when I breathe or move. Today I woke up and now my neck hurts too. It is one of the worst pains I have ever felt. I took tums and some acid reflux medicine to no avail. thanks [/INST] Thanks for your question on Chat Doctor. I can understand your concern. Possibility of musculoskeletal pain is more likely. But better to rule out cardiac pain first because of obesity and left sided nature of pain. Get done ECG and 2d echo. If both these are normal then no need to worry about heart diseases. Avoid movements causing pain. Apply warm water pad on affected areas. Take simple painkiller like paracetamol or ibuprofen. Don't worry, you will be alright with all these. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks. </s>