<s>[INST] My sister who is in her late 40s but otherwise very healthy is having headaches, dizziness and feeling tired. She has had an EKG, blood work and other tests, but nothing has come up. She has low blood pressure and her heartbeat rate is very good - that of a runner. We noticed she has indented temples, which is something new. What could be going on? [/INST] Hi, The most common causes of headache are migraine and tension headache, which can be treated with medications. If in doubt, brain scan may be needed. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Sudhir Kumar, Neurologist </s>