Yeah as soon as i saw this thread i had to enter, cause i had this, until last year! It just magically vanished after a year of pain and aching whilst skiing, trampolining etc.
THe longer name for it i think youre after is called Patellar Tendonitis. The medical term for this... horrible illness.
Vibes man, i were told by my doctors it wouldnt go away in about... 3-4 years. It went away after a year.
I first started to feel it by the end of lastyears / 2010/2011 season ( i think ), because thats when i started practicing flips, going biigger and not railing as much as i had been doing in the past. Kindof panicced, cause it never truly went away, - trampolining in the summer was a nightmare, could jump for about 5-10 minutes and then i had to ice my kneecap, and the surrounding areas.
Started training my knee again, holding heavy stuff in both my arms (weights? Manuals?) and doing exercises that would help strengthen my knee, while watching TV or something.
So to sum things up a bit, if i were you, i wouldnt stop skiing a bit, because i never really did, nor did i stop jumping trampoline and doing such things, but when it started hurting doing those things, i would take a break.
It went away, way faster than expected so keep ya head up and dont start limiting your... stuff you want to do (hahaha)
good luck maan, vibezzzzz