Recurring ear infection. Child his age?

Hello, I’m concerned about my 3-year-old son, who has a recurring ear infection—this is his second in two years, and I suspect it may be otitis. His ear appears swollen, larger, and slightly popped out compared to the other side. He’s been fussy, tugging at his ear, and seems uncomfortable lying on that side. Last time, he was treated with antibiotics, which helped, but I’m worried about potential chronic or underlying issues making him prone to these infections. Could you advise on possible causes, preventive measures, and whether a specialist visit is necessary? Additionally, could you suggest essential medications to keep on hand, including antibiotics, pain relievers, and ear drops, suitable for a child his age? Guidance on dosages and safe options would be much appreciated. Thank you.