3 weeks ago I suddenly fell to the floor I
Nerve damage since trauma.
Hello dear, welcome to Ask a doctor service.
I read your query and here is my advice.
I think you should have gone to doctor at the moment of the fall to be checked for fractures or trauma.
I think you still have to go to doctor for an x-ray of cervical spine. A neurologist should also check nerve conditions. I think this situation is caused by trauma in nerve causing weakness of neck extensor muscles.
I believe you may need physical therapy to get back to normal.
Hope I have answered the question
Let me know if I can assist you further.