My son is 21 years old and has been diagnosed with type 1 diabetes for 5 years. He has been having severe foot pain and started taking gabapen 3 weeks ago. The pain is not improving and the side effects are horrible. He is thinking that this may be something not diabetes related. His symptoms are severe and constant foot pain that is worse at night and in the morning, upset stomach, chest pain, fatigue, itchyness, tremors. Any suggestions on what this could be?