I have a light switch that handles 4 chandeliers (3 60 watts bulbs) and two ceiling fans. If switch is on for awhile it is warm to the touch. Should I install a heavier switch?
Unlikely that the switch isn't heavy duty enough. But the contacts in the switch and/or the connections to the wires may have problems. I suggest replacing the switch just in case it is having internal problems. When you do that, check the wires for any evidence of arcing. If the wires are not in good shape, cut off the end and strip a new section to attach to the screw terminals on the new switch. Obviously turn off the circuit at the breaker before doing any of this.
Most likely you have a standard 15 amp switch, and probably the cheap one to boot (Standard vs Preferred, as Leviton likes to call it). It could be worth going up to at least the beefier switch. I doubt you need a 20 amp here.