Hi, Noted your history about having diarrhea to all the friend on a visit to Portugal and you developed additional swelling of the collarbone and pain in the right shoulder. Since all your friends including you developed diarrhea means there was enteric infection by oral route due to infected water or food that you all must have taken together. Such a severe intestinal infection can cause septicemia meaning spread of the infection through blood route and thus get isolated focus of infection. Hence the condition should be taken seriously unless proved otherwise. I would advise you the following in such a situation : Consult a General Surgeon for examination of the collarbone to find out the cause whether infection . Get blood culture and sensitivity along with WBC and electrolytes, kidney and liver functions. Get appropriate antibiotic, metronidazole treatment for 5 days. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, ENT and General Surgeon