I hate to offer you a welcome to the club, but.....well......you know.... 😀

Your story is exceedingly common. An ECG while you are flat on your back, probably calm after waiting a while for it to happen, and nothing shows.....it's typical and unfortunate. Your cardiologist, if you have one, should offer to have a Holter monitor or a Zio Patch applied to run for several days. If you get ectopy most/every day these years, then it should show up, but not likely to on a 10-15 second ECG.

You are, in my inexpert and non-trained opinion, a prime candidate to see an electrophysiologist (cardiologist trained in electrical disorders who do catheter ablations to help stop arrhythmias and who would install pacemakers). What doctors of all kinds, looking after many different disorders and conditions, want for you first is relief from symptoms that rob you of security, peace, and that keep you uncomfortable anxious, and/or in pain. Not that they don't want to also control or to fix problems so that you don't continue to need interventions and medicines, but they want to make you feel better. An EP will listen to you carefully, but also look at several indicators of your heart structure and function. An ECG, probably an echocardiogram, maybe a stress test result, and possibly a CT angiogram to look for blockages or heavy deposition of arterial plaque. A heart acting up sometimes just lacks oxygen, also called ischemia. If those can be ruled out, and you're otherwise healthy and active, no other serious comorbidities that need attention or that might make his work pointless, then he/she will probably offer an ablation or some other suitable treatment. But you have to see him/her first and get to know them. And they you.