Hi. Hope you are recovering well from your past injury. I have thoroughly read your query. Heaviness of head has a multiple causes to it like 1. head and neck injury ,2. fatigue (happens because of lack of excercise and poor health) , 3. migraines, 4. vertigo , 5. anxiety and depression , 6. illness causing weak health. In your case , head and neck injury is most likely , then comes to lack of exercise and your healing injuries and poor health. we still cannot leave anxiety. So to get to a proper line of managent to your issue , you need to see a physician in clinic to get yourself evaluated to rule out above causes and get treated. With h/ o Previous head injury, post traumatic head heaviness can occur months after the injury , but mostly associated with other symptoms like burning or tingling sensation and increase pain on soft touch. As you have not mentioned anything about this , neck muscle injury has to be considered for your symptoms. Neck muscle injury usually gets evaluated by a MRI. So its better you meet a doctor in clinic and get yourself physical examined and investigated for further management. Hope this is helpful . Thank you.