Hi Mary,
Your story sounds similar to mine- sick sinus syndrome that left me with both tachycardias and bradycardia. I had a dual chamber pacemaker ( St. Jude Assurity) in June 2019, and I can tell you it was a game changer for me, I felt so much better.
I think the only time I felt any real pain from the surgery was maybe 2-3 hours afterwards. I was still in the hospital for several hours monitoring after the surgery, with plans to go home later that day if everything was ok. I guess it was when the local anesthesia had worn off, but I felt a deep ache from the surgery site up to my shoulder, jawline and down my left arm. The nurses offered me my choice of several painkiller meds, ranging from oxycodone, to Motrin ( I think) or extra strength acetominophen ( 500 mg). Well, the "good stuff" ( ie, oxycodone tends to upset my stomach, so I chose the acetominophen, and that cleared up that pain within a short time! I didn't have a repeat of that pain, and I found that the extra strength acetominophen took care of any residual pain I had after that.
I took acetominophen PM ( 500 mg acetominophen with benedryl) before bedtime for about a week-10 days, and that helped me sleep well through the night- I slept on my back as that was more comfortable while the surgery was healing.
The incision stung a little bit, itched some as it was healing, and sometimes there was a feeling that some have described as "ant bites" there from what's likely the nerves protesting at having been insulted. I felt the slight weight of the pacemaker there during that time, with a feeling that I can only describe as someone having pinned a corsage right onto my bare chest!
It didn't take long at all for any discomfort I had to go away. I'd say after a few months, you probably won't even feel the pacemaker anymore, and if you're like me, after a number of years the scar will be almost imperceptible too. I can go days without even thinking of my pacemaker, except when I do, I can only be grateful for the good it has done me.

Best of luck to you- you'll be a new woman afterwords!