Don't ice.....inflammation is your body's healing mechanism.........RICE treatment was developed to keep paid atthletes in the game (seen as expendables for sports entertainment) along with cortisone shots...................you don't have an owner makng money off of you......go get prolotherapy and strengthen those outside ligaments............and tendon attachments........

This sounds like ITB Syndrome.  There's a sheet of tissue that runs along the outside of the thigh from the pelvis to the outside of the knee.  This tissue becomes inflamed (usually from over use, or from your general leg structure [commonly bow legs]).  It also can come from running on cambered roads.

I use a foam roller to get it to relax. When you find a hot spot--lay on it for a few minutes (yes, it will be painful).   I also do stretches specifically for the ITB (see YouTube or Google for instructions on how to do these) after every run.  The RICE methods has been very helpful for me.  NAIDs may also be helpful (please do not take anything until/unless you see your doctor first) to reduce the inflammation.  You may find it helpful to use a Cho-Pat knee strap to wrap around your thigh just above the knee to help stop/reduce the friction (movement) of the tissue over the outer knee bone. 

When my ITBS gets too much I reduce my miles for a few weeks.  Some people substitute running w/cycling or the elliptical if their legs allow for it.  Please see your doctor if the pain persists just in case it's not ITB.  Other knee injuries can also mimic ITBS.

Good luck to you, and happy running.