Hello, For stage one breast cancer - lumpectomy is the usual procedure done and post this radiotherapy and chemotherapy based on the requirements of the body to kill the left out cancerous cells. But most people opt for Mastectomy full, because of having no left out cells to reoccur. The symptoms like - back pain, stomach burning, lightheadedness, and throat dryness is common in patients who are undergoing either radiotherapy or chemotherapy. As this therapies are high intensity radiation and chemical composition they make the body weak and this is the most common complaints which patient undergoing radiotherapy or chemotherapy have. As the body tends to become weak from inside to destroy the cancerous cells back pains are common. Due to excessive heat in the body, the throat becomes dry and so does your symptom. Also, stomach burning due to excessive loss of water from the body as the body is fighting against the cancerous cells destruction method of radiotherapy. I will advise taking good rest, plenty of water, simple low-intensity general exercises. Wait for this radiotherapy to get over and you will notice changes in the body and the symptoms will reduce as well. Research has supported the effect of physiotherapy in pain management in cancer survived patients. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist