Is Compost Bin Affecting Growth Of Garden

I have a compost bin which I've started with the right ingredients no meat or fat or grease all vegetable waste and fruit waste. It got a little wet though while I over watered it and I've gotten flies and smaller flies and the house hold like flies. Istir it and add soil to lessen the bad smell. My concern is does methane gas which i think it releases. Does it affect the growth of my tomotoes which are about 20 feet away? I know they thrive on CO2 but does methane help or bother them? They seem to be wilting. 7 of my 15 plants I'm thinking not enough water or someone recently watered during the day in the hot sun. Then I was wondering about the compost bin and its gas flow.

Methane does not harm plants. It harms the climate because it heats the atmosphere 22 times more than an equivalent amount of carbon dioxide. I have some tomato plants adjacent to my compost heap and they show only lusty growth. The wilting was probably because of the hot and dry 2012 summer. It is a temporary problem, since the plant tries to make more roots to compensate for the more than average rate of transpiration.
Watering in the middle of the day would make the plants open their stomates because of the sudden wet and chill and then when watering stopped, the open stomates let more water escape than the roots could replenish. It may even kill some of the leaves. If you must water in the hot sun, don't wet the leaves.
Another problem could be that the heat was so intense that the soil under some plants became so hot that the top layer of roots got cooked. A good mulch will prevent that.