Hi Michael,
Pain of any kind is cause for concern, especially long term pain like you are describing.
Anytime you have pain in your penis, it's best to see your doctor particularly if there is a noticable difference when you are urinating. You can read here in the symptoms database, information about pain in the penis. Some common causes are listed below:
Common Causes
* Injury (such as that due to too much manipulation) * Bites, either human or insect * Pimples * Genital herpes * Inflammation of the prostate gland (prostatitis) * Syphilis * Nonspecific urethritis caused by chlamydia or gonorrhea * Infection under the foreskin of uncircumcised men (balanitis) * Reiter syndrome * Priapism (persistent erection that does not go away) * Peyronie's disease * Cancer of the penis * Infected penile prosthesis * Sickle cell anemia
Remember, online sites are great resources for information so that you are able to ask the important questions that will help you manage your healthcare, however they can not take the place of your doctor's solid medical advice.
Hope this helps. Please stay in touch and let us know how you are doing!Vicki M