I am having pain down my leg to my knee. Is it possible that I have a pinched nerve?

Your pain is called pseudoradicular pain. Traditionally, it was felt that only pain that radiated below the knee, called radicular pain, could be caused by a pinched nerve in the back. A pinched nerve is a nerve root that is being compressed. However, a recent study has shown that standard neurological testing, particularly of sensation, may not correctly diagnose leg pain. In fact, in some cases, pseudoradicular pain may actually be caused by nerve root compression.

R. Freynhagen et al. Pseudoradicular and radicular low back pain: A disease continuum rather than different entities? Answers from quantitative sensory testing. Pain. 2008. Vol 135. Pp. 65-74.