Reoccuring side lower back pain/cramping w/numbing down my leg and up my back

When I wake up in the morning, I have a cramping on my right side lower back and lose of feeling on that side.I have noticed a red rectangular inch in length,half inch in width mark on my right side lower back that will go away w/in minutes after I get out of bed but will come back if I sit down in a chair for a while only to disappear w/in minutes when I stand up again.  I sleep on my back and the mark on my back is almost like something around my kidney is pushing outward on my skin making it red.  What could this be, why does it go away and come back  and could this be the reason for what feels like a pinched nerve on my right side?  Thanks!