What Casues Sharp Pain In The Lower Leg?

I have sciatica, which I have had for years. I have been doing an intense 1 hour work out 3 times a week. Sometimes I feel good and sometimes I feel the pain in my right leg when I get home. Especially when I go to bed. This evening when I was running, I felt a sharp pain in my right lower leg so I started walking. As I felt better, I started running and again felt the pain in my lower leg. Only this time I felt pain in my right hip and lower leg. The pain is on the outer side of my leg. I don t normally feel this when I run. Can running trigger my scatica this way? Also, is there anything I can do to relieve the pain I feel in my right leg when I go to bed? It is very very uncomfortable. This pain is almost every night. I toss and turn and deal with the pain until I fall asleep. (sorry I was so long winded) Any information is greatly appreciated. Thank you Smoore