I would consider x-rays and MRI.
Possibilites could include:
a fractured hip - usually makes walking extremely difficult or not at all.
Compression fractures in the spine
Sciatic Nerve inflammed.
THese need to be investigated. Your provider may not be doing them due to his age. But you can request that he be more aggressive with diagnosising.
Hello, Welcome to Just Answer and thanks for your question. I'm afraid you are confused about pain management. They do not "go farther" to find the diagnosis of a problem. Their only job is to make the patient more comfortable. If you are looking for further help with the diagnosis of what is causing your father's pain, you may want to contact a geriatrician in a large teaching hospital near your home. Geriatricians are physicians who have additional training in managing illnesses in the elderly. Just Answer cannot recommnend specific practitioners because we have no way to check their credentials.
Then that means that she (the geriatrician) may be stumped for a cause and is sending him to pain management to make him more comfortable. I would suggest you have a talk with her. Actually, she may know the cause of the pain, but there may be nothing that can be done to eliminate the cause because of his age of physical condition. An example would be a pinched nerve in a patient who is too frail to undergo surgery. In that case, controlling the pain is the paramount consideration.
Then perhaps you really should push her, or consult with another doctor, for a diagnosis if you don't want to go the pain management route. That would seem to be the better plan.