Is It Harmful To Take Expired Medicine?

I am a 68 yr old woman with diabetes Type 2 and hypertension both under control with meds. I have gotten a stiff crick just above my left shoulder blade between neck and arm where I think I fell asleep in a weird position in my chair. I ve had this before and Ben Gay always works. But my unopened tube has an exp date of 2013/01 --is it still good? I also went to WWW.WWWW.WW to check for interactions with my meds and there are none. I had a small stroke stroke --some called it tiny in late August due to stress, hypertension and uncomtrolled glucose. I went on metformin & have been normal since. BP is also good.