Some have it; there is no problem with it.
Penis size.
Some causes of painful urination can be a Urinary Tract Infection or possibly prostate problems. It is always good to see a doctor if painful urination persists.
Uti Possibly
There are several symptoms of the BPH prostate such as difficulty starting a urine stream, decreased strength of the urine stream, dribbling after urination, feeling that the bladder is not completely empty, an urge to urinate again soon after urinating, pain during urination.
BPH produces a swelling of the prostate gland that obstructs the urethra. This causes painful urination, reduced urine flow, difficulty starting or stopping the flow, dribbling after urination, and more frequent nighttime urination.
A good kegal exercise for women is to tense your pelvic floor muscle as though you are stopping urination mid-stream. Be cautious to not stop urination mid-stream, as it can cause bladder infections. The Mayo Clinic's website has an excellent list of suggestions: www.mayoclinic.com/health/kegel-exercises/WO00119
If the toenail is too long or if it is dry, then it will split.
Since the urethra passes through the prostate, when the prostate enlarges it presses on the urethra and causes problems with urination. Including the inability to completely empty the bladder, increased urgency, and difficulty starting the stream. Men might experience difficulty during intercourse because of lack of libido and painful ejaculation in addition to the pain during urination. Avoiding prostate problems might involve taking supplements.
a stream is most likely widen by erosion
Flooding
Medications with anticholinergic effects can cause dry eyes, dry mouth, and difficult urination or defecation.
ADH
A mature stream causes more erosion than a young stream, due to the pure fact that theres more curve in a mature stream causing the sediments to shift more frequently.