I don't really work out, I would run or bike occasionally, but nothing hardcore. Saturday I ran a 5k, then Sunday I biked 12 miles, and I'm having pain from my sciatic nerve (sometimes I feel the pain shooting down the back of my right thigh). Today I'm supposed to "run stadiums" with a group of people (running up the stadium's stands and such), and I'd really like to not wuss out if possible. How can I relieve this pain? What am I doing to cause it, or what am I doing wrong?