Flickering lights may be a sign of a defective or loose light bulb. If replacing the bulb doesn't solve the problem, consult a licensed electrician. The fault may be in the light fixture.
Also, either the connections to the fixture or your home electrical wiring in the circuit breaker box may be loose. This type of electrical problem requires professional diagnosis to ensure a complete repair.
Hot ceiling fixtures
You should occasionally check the area around your ceiling light fixtures for warmth because not all fixtures are well insulated. In addition, if you exceed the maximum recommended wattage for the bulb, the fixture can overheat. Too much heat buildup could pose a fire hazard.
Switching to compact fluorescent light (CFL) or light-emitting diode (LED) bulbs provides one solution, because these bulbs don't produce as much heat as incandescent bulbs.