I would recommend you to go through this link. It has clear description of your problem. However, I've tried to extract needed info.
Many types of events rely on a responder chain for event delivery. The responder chain is a series of linked responder objects. It starts with the first responder and ends with the application object. If the first responder cannot handle an event, it forwards the event to the next responder in the responder chain.
A responder object is an object that can respond to and handle events. The UIResponder class is the base class for all responder objects, and it defines the programmatic interface not only for event handling but also for common responder behavior. Instances of the UIApplication, UIViewController, and UIView classes are responders, which means that all views and most key controller objects are responders.
In your Case, when you are writing event methods in your customTableViewCell class, your methods are not being called. this is because, TableViewCell is not participating in Responder chain.
next thing is, check whether "User Interaction is enabled " or not for your Cell. You can find it under View section of "Attribute inspector".