Look at these two threads. I made an appt with an Osteopath today. I have burning at the tip of the penis and my Doctor and Urologist can find nothing wrong. My lower back started killing me a couple of months ago... a week or so before the burning started. I thought the back pain would go away because I have arthritis... but it hasn't (like the other places on my body have). I was getting ready to get my lower back checked out anyway and some internet searches have kicked out some interesting things out on this subject (in regards to back pain and sacrum alignment). Good luck.
http://www.medhelp.org/posts/Mens-Health/Vibration-sensation-in-penis/show/183034
http://www.medhelp.org/posts/Neurology/Burning-at-Penis-Tip/show/326612
Hello and hope you are doing well.
Hope diabetes has been ruled out. The causes for the burning sensation on the penile head are dryness, yeast infections, herpes, sexually transmitted diseases, genital warts, allergies and balanitis. It could also be due to pemphigus, aphthous ulcers and cancer. If there is accompanying swelling, redness, discharge and fever it is most probably an infection. As most of the causes have been ruled out, it could be due to allergies, herpes or pemphigus.
Hope this helped and do keep us posted.