Hey, a longtime lurker who registered just to post a reply to this message. Please do forgive me if I make any newbie mistakes! 
Who am I?
I’m not a doctor, a sports specialist, a PT or a chiro. What I am is a 28-year old avid distance runner, climber (rock) and amateur footballer who is also into some bodybuilding for aesthetics (ie, for the chicks! Heh!) Oh yes, and I have struggled with the exact same injury you have for the last 2-3 years.
I’m also passionate enough about running and fortunate enough to earn enough to be able to consult some of the top sports doctors in my nation to “fix” my injury. I’m no expert but this diagnosis comes from the doc who used to consult the national olympic track team (yeah we’re shit but he’s a good doc).
What you have is most probably a form of IlioTibial Band Syndrome (ITBS). Also known as “Runner’s Knee”.
Unfortunately for you this sort of injury is uncommon among bodybuilders. But on running forums you’ll get plenty of responses.
I can only share my experiences and what the doc did and told me:
a) Your injury will hurt like a bitch for a bit. Walking on flat ground will eventually be pain-free but up and down especially on stairs will be a bit tricky for a while.
b) RICE and foam rolling help. Ice the injured part near your bursa 2x a day, in the morning and evening for some pain relief. Foam roll, and during the day, put two fingers over the bursa (the bumpy bone in your knee where you feel the pain) and massage gently to break up scar tissue.
c) In my case, I’m somewhat flatfooted, and the doc told me that my bodybuilding actually contributed to the ITBS and worsened it. Although I don’t over or underpronate particularly noticeably while running, all those squats, hamstring curls and glute raises have contributed to muscle unevenness in the legs. Although typically our quads and glutes are oversized, we fail to work the hip adductors, iliacs and all the minor muscles that act as stabilizers, so when running particularly far or particularly fast for too long leads to poor form and ITBS pain. You may also already have poor running form, or, push yourself too hard too soon.
d) The good news? It can be helped. Aside from the slow fixes (RICE, foam rolling) you can use cortisone injections, electrotheraphy and ITBS release (sports doctors who specialise in Track and Field athletes would be best) will help ease the pain. Beyond that, stretching, knee braces, better running form will help keep ITBS at bay once you do recover. But the bad news? Recovery is bloody slow. Most docs will ask you to stay off the knee with high-impact activities (ahem, sprinting, long distance running, sprint swimming) for AT LEAST a month. Sorry mate.
e) The worse news? ITBS will most likely (unless you are bloody lucky) always, ALWAYS be with you unless you consider something radical like surgery. I was fit (“athlete-level fitness” according to the doc) when I started having trouble, rehabbed, came back, and still struggle with it every day. Mostly, for us distance runner folk, whatever you do, can help keep it at bay temporarily, but never get rid of it. Example, if you used to do 23km at 12km/hr pain-free before your knee starts giving way, with proper stretching, bracing, etc, you may buy yourself 30km at the same pace before it starts to bother you. As a result I hardly now do anymore marathons (last was 2 years back, suffered hell after 30km and limped home in 5h40m, 2 hours to cover the last 12.2km) and restrict myself to all-out 10k runs…
BTW, BBB, I have a tremendous amount of respect for you, would like to ask you (OT) why is it you think both my knees pop a lot? They crack like rice krispies whenever I squat (even without weights, especially if I havent bent for awhile). Doc I saw said most docs don’t understand crack/pop sounds, and the knees were “fine” (they still are, no pain, at least).
However, the crack does bother me, especially when you’re squatting 240 and you hear the pops go off once you go ass to ground…it just sounds wrong!