'99 Accord misfire

I have a '99 4L Accord DX, 5 spd manual. The check lamp had been lit then started blinking, with noticable loss of power, enginie missing in fifth gear. Then began roaring like muffler was shot. Mechanic diagnosed cat gasket and replaced. Car runs almost normally, but runs rough while idling and in low gears. Don't notice miss at highway speeds. Check light still intermittently blinking/or just lit. Comes back with misfire diag code. Mech suggested a tune up, then after testing plugs advised that it's a compression problem and could be a valve. Suggested replacing motor is only fix due to high miles. Someone else mentioned the ignition coil as a possible problem. Car has 200k miles but was running perfectly before initial problem. Will an ignition coil cause the misfire code? Should I have a compression test done? Thanks.