OK, there is a good chance you are correct, i.e. that a prescribed medication was influenced by a drug companies rep. It is a common issue.
The real question remains, is it appropriate.
You went in with pain, of unknown cause, and the doc gave you a medication.
There are two approaches to manage pain with drugs, mask it with narcotics, or non-narcotics, or attempt to prevent pain signal transmission and propagation from the source to the brain.
Lyrica is a newer drug in the latter group, and is used for assorted neurogenic pains, including that caused by the neuropathies of diabetes and others.
In any event, your doc felt that this was an appropriate choice, but if it is having unpleasant side effects, clearly, there might be better options for you.
First thought is to get a second opinion as to the source of the pain, and secongd thought is to try other drugs that are similar (neurontin etc.)
Go see a pain specialist or a neurologist if you are not getting anywhere.