I Am Having A Lot Of Difficulty Lately Finding Words.

I am having a lot of difficulty lately finding words. I know what I want to say in my head but am having trouble getting the words out. It has been getting increasingly worse with at least 2 episodes daily. I am not on any medication consistently but have bad back pain and on occasion I do take muscle relaxants and pain killer s prescribed but have not taken it in at least 3 weeks.