What Causes Irregular Heartbeats?

I am having irregular heartbeats. When checking my pulse it will beat a few times then hesitate, it started doing this yesterday. My shoulders hurt somewhat but I think that is normal for me. I have eight stents in my heart, one in the abdomen and two in the sub clavian area. I have also had both carotid arteries cleaned out. I have had two small strokes, one about four months which , according to my Neourologist, I must wait on intensive dental implants for all teeth. My question is with the hesitation when checking my pulse and the funny feeling in my chest, how should I approach this?