Why is my 2003 dodge grand caravan not starting every now and then?

[Amber W]

I have a 2003 three dodge grand caravan and my latest weirdness is that when I was out of town last night, I got in turned the ignition and it wouldn't start all I could hear a click. So I turned it off and tried again and it started. When I arrived back to the hotel I tried it again by turning it on and off and it happened again, but hasn't happened at all today from that point on. Someone told me it may be just a look plug of some sort. Anyone have any suggestion. Also it has been havign some weird sond, it kind of sounds like a robot sound errrrrrrrr not like a motor sound. Someone suggested that this was powersteering pump, but I am not sure if this is connected with the starting thing? Any advice at all will be appreciated