if it only happens when you're high, it is probably anxiety. everybody has some weird pain somewhere every once in a while, but anxiety issues can change the way you look at them, and make you feel it more and more. like everytime you smoke weed now, you will expect it to happen, and thus it will only become worse over time. people with anxiety issues (I am one of them btw) also tend to think that there might be "something wrong" with their body, and so they obsess about every little thing their body does and interpret it as a "symptom".
stop smoking weed, do healthy stuff and don't overthink this shit too much. If problems get worse anyway, go to a doctor.