Shoulder crevice pain may have the following causes: first, myofasciitis, myofasciitis patients can be the first symptom of pain in the medial gap of the shoulder, and then can radiate to the ipsilateral shoulder and upper limbs, appearing soreness, weakness, can sleep at night when pressure, exertion pain, numbness is very obvious; second, gallbladder or heart disease, when the gallbladder appears cholecystitis, gallbladder stones or When the gallbladder has gallbladder inflammation, gallbladder stones or heart attack, angina pectoris, there will be pain on the left or right side of the shoulder crease, then we have to perform ultrasound, CT or cardiac imaging, ultrasound, ECG for early diagnosis and treatment; third, lung tumor, if there is a tumor in the upper lobe of the lung or the tip of the lung, there can also be shoulder crease pain, then we have to perform CT lung examination for diagnosis.