Hi, There can be various reasons for your back pain. It can be due to anemia, lack of proper exercise, abnormal posture, urinary tract infection, arthritis or vitamin deficiencies. Even stress and anxiety can also lead to such symptoms. Besides, it can be due to problems related to diseases of the back (lumbar disc disease), or muscle strain. Tab Losartan rarely can cause muscle and back pain (by causing skeletal muscle damage and kidney disease). I feel that first of all focus on your diet. Eat plenty of fruits and vegetable and drink plenty of water. Maintain proper posture especially while sleeping, standing or working on computer. Try to do some abdominal and neck muscle exercises. Maintain adequate weight. Also if still your symptoms persist then go for some investigations like complete blood count, FBS, TSH, X-ray lower back, vitamin D and urine routine. This will give you a proper diagnosis. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Milinda Gupta, Internal Medicine Specialist