Consult pain specialist for complete clinical examination nd evaluation and start treatment accordingly

Your husband has got on and off headache on back side related to posture. Moreover he is a young IT professional and presuming he spends lot of time sitting in front of computer in a particular posture which can produce lot of musculoskeletal strain on the neck and back of head. It's very unlikely that he has any underlying sinister cause considering the duration and no other symptoms. It's advisable to consult your doctor and he needs to be examined thoroughly including examining the back of the eye and acuity of vision. Migraine also needs to be ruled out Maintaining good posture, exercise, muscle relaxant and painkillers like paracetamol may be helpful.