Slipped and hit head first on floor 2yrs ago had moderate pain in head & neck now headaches are severe & feel like head is going to explode ?

Did you get checked: Out after the fall? Have you had any other head trauma or neurologic signs? If no other changes, suggest seeing a physician and having them take a look at your cervical spine as well as rule out any other serious issues. After a fall, many times docs forget to look at the neck musculature (too busy trying to rule out life threatening issues!) but this can lead to long term neck issues/headaches.