Hilly Miles and Hurting Back...Ugh!

My back is killing me! I am not sure if I injured it when I fell the other night or what. I've been having some mild back pain for a couple of weeks...but it never hurt while I was running. This morning it was hurting while I ran...especially when I tried to increase my pace. I am really frustrated and depressed about this. Why can't I just run...with nothing on my body hurting? It seems like something is always hurting...shins, knees, now my back! Ugh! On a positive note, there was a nice breeze this morning...I guess from the Tropical Storm in the Gulf. We ran 3.96 miles in about 46 minutes so an average pace of 11:36. I am planning on taking a few days off to see if this pain gets better. I have a long run (about 11-12 miles) planned for Sunday so I am hoping I will be all healed up by then.