I Recently Was Giving Plasma, And I Have Had A

I recently was giving Plasma, and I have had a cell loss twice in a 8 week period. When they were trying to put the blood back in the vein, it would not return. The blood was just going in my arm. I felt the pressure at the time, and the person told me that the blood would clot under my skin and it would eventually go away. Very soon after that happened, I have been having back issues. My middle to upper back feels strained. It hurts to move and also when I breath. Most of the pain is only when I get up from sitting. Ice does not seem to be helping or does Motrin. Please advise.