I am on bilocor 2.5mg p/day for the past 2weeks. for last 3days i have pain in & around my ear. can this be an allergic reaction to bilocor?

Not likely, but...: Not impossible, either. Any medicine can cause anything in certain individuals. A person may have a side effect that is rare, or has never been reported before. However, this is not a usual presentation for allergies. Get examined first before stopping it, to be sure it is not due to something else, like an infection or ear wax problem, or TMJ pain. All these are far more likely to cause pain.