I feel some discomfort in my urinary sphincter. is that a symptom of urinary incontinence?

Sorry but I do not think you can feel your urinary sphincter. Urinary incontinence occurs when you can't voluntarily hold your urine or you leak your urine easily when the bladder is not quite full under an external pressure such as cough, sneeze or even laughing.

As you get older your sphincter shrinks causing your bladder not to empty completely. The muscles in the bladder and urethra lose some of their strength causing involuntary urine release. See a urologist for exam and treatment.