What Causes Elevated CRP Levels?

Hello Doctor 4 blood tests in the last year. All OK except C Reactive protein levels - ranged from 11.2 to 13.8 mg/l ( I am 52, have MS for 16 years. My mobiltiy is with a walking stick. My left leg simplty does not lift properly off the ground - drop-foot on that side. This leads to less exercise escpecially as fatigue sets in after 20 minutes standing. That means certain functions suffer due to lack of movement. Diet is very good. When I pass stool, it is very well formed, hitting the toilet water before it breaks up. Perhaps too dry, and at times a strain to pass, maybe becasue of how long it is? I do not drink enough water. Maybe an extra lite a day is required.