<s>[INST] I laughed very hard and now my upper chest hurts. Though, the pain is dull when im not laughing. After a while it goes away, but then I laugh hard again and it hurts. It just started a few minutes ago when I was running and playing with my little niece. [/INST] Thanks for asking your question I completely understand your question laughing out loud may cause muscle stretch and cause problem.u may take an analgesic tablet for one or two days and if pain gets relieved then it is nothing to worry or if pain remains then consult a pulmonologist, he can have a chest X-ray and rule out any other cause. Do not panic it's going to be thanks/ regards feel free to ask more questions may god bless you with good health </s>