Burning in tip of penis that comes and goes and also in legs . neg test for stds and uti. i have lumbar spinal stenosis.could it be that?

Yes: Spinal stenosis is found on studies in 20% of the population by age 60 with symptoms ranging from none to a lot. Pain into the legs due to stenosis is due to nerve compression & this can also occur in the perineal region & over the penis due to compression of the nerves that supply that region as well. Typically it is brought on by standing & walking & relieved by sitting or bending over.