yes, sticky keys mean that the keys are stuck once it's pressed ... and it doesn't mean that surface needs to be cleaned =)
anyway, make SURE that the heater is one all the time ...
cuz it's the one that regulate the temperature...
if ur heater is not on, or not on for a period of time, try switching on for 2-3 days and see whether the problem is fixed
if it's too bad and not fixed yet, you need to call in a piano technician, and believe me it'll cost more than 50-100 dollar (a good technician of course, dun go to the bad one, can't trust piano to just anyone) because 50-100 dollar is the fee for TUNING only, which means, they only do tuning for the piano. If you want him to do anything else for you, the technician will usually charge differently, e.g. toning the piano's hammer ...