No app can actually boost your signal... and some of the "real" booster apps that just tweak some of the settings to improve the speed make such a minor difference that they are not worth it... I have heard some of those apps do improve performance for GSM-type phones (AT&T, T-Mobile, overseas) but Verizon uses CDMA technology which these apps would have no affect or possibly even a negative effect on.
That being said, Go to Settings - Applications and find the culprit app and uninstall it and reboot. If that fails it looks like it's time to do a factory reset. If the factory reset doesn't help, might be time to go see Verizon.