One ear clearing better than the other is extremely common, and not a cuase for worry. You could visit an ENT, but the odds there's nothing to be done except maybe using drugs to reduce or prevent congestion for better air flow. I prefer to avoid any unnecessary drugs, but that'll be your call.
Your problem gets progressively worse because you're slightly behind the curve on clearing and with each dive subjecting delicate tissues to mild barotrauma, leading to swelling, sensitivity and/or fluid in the middle ear space. With fewer ascents and descents in a day you have a chance to recover and might not even notice, but multiple dives make it progressively worse. It's like getting a bruise, the first shot hurts, and now even a tiny tap that you wouldn't have otherwise noticed, hurts like hell.
Clear your ears faster and gentler, descending slower if needed, manage bouyacy to minimize pressure changes during the dive, give your ears a chance to recover, and you'll be fine. As your diving and equalizing techniques improve this will become only an occasional problem.
