Hi thanks for asking question. According to history you Hodgkin lymphoma history . Now you have pain at chest and shoulder. Although you are treated possibility of metastasis has to be thought. For that yes x ray can be done. But if x ray picture not clear then CT scan or bone scan like investigation done to search for metastasis. If metastasis not present by above investigation then it might be by muscular strain or by costochondritis or myositis like picture. For pain take analgesic . Along with my above suggestion also consult doctor for physical examination as you have malignancy history. Good luck.