Pacemaker implantation places a small generator and wires to keep your heart beating regularly. The “symptoms” patients notice are usually normal post-op changes or early warnings that the device or wound isn’t behaving. Chest-shelf ache is typical. A deep, bruise-like pain around the incision and under the collar-bone can spike with arm lifts or deep breaths and fades over two–four weeks. Device bulge is normal. A hard, match-box-sized lump under the skin is the generator; sudden swelling or warmth suggests bleeding or infection. Brief hiccup-like shocks are common. Tiny muscle twitches in the chest or arm occur while the lead... Learn more