Happiness and charity have a bizarre relationship in our society. Everyone is chasing one and being chased by the other. What if you could solve both dilemma’s at once? Science shows that giving brings about happiness. Many researchers have done many styles of research and have empirically shown that giving causes pleasure in human beings. Philosophers hinted at this with various theories but now we have the science. Let’s start with cognitive neuroscience.
With the help of functional magnetic resonance imaging (fMRI) scientists have been able to test what areas of the brain are active while people perform various tasks. In one study, areas of the prefrontal cortex became active when the test subjects engaged in giving. The same area associated with the pleasure response.
Looking from evolutionary sciences; Dacher Keltner, co-director of UC Berkeley's Greater Good Science Center has said, "Human beings have survived as a species because we have evolved the capacities to care for those in need and to cooperate."
Even Darwin speaks of Benevolence 99 times in his work “The Descent of Man”
Which brings us to social psychology. Social psychologist Shalom Schwartz has identified 10 Universal Human Values. His theory has been tested in 62 different countries and his values have proven to withstand cultural differences. These values are based on the fact that they address three universal requirements of human existence; 1) individual needs as biological organisms, 2) coordinated social interaction and 3) survival and welfare of the group. As human beings, we require a connection with fellow humans. One of the ten Human Values Schwartz identified is Benevolence.
Schwartz defines benevolence as:
“ Benevolence values derive from the basic requirement for smooth group functioning (cf. Kluckhohn, 1951) and from the organismic need for affiliation (cf. Maslow, 1965). Most critical are relations within the family and other primary groups. Benevolence values emphasize voluntary concern for others’ welfare. (helpful, honest, forgiving, responsible, loyal, true friendship, mature love) [sense of belonging, meaning in life, a spiritual life].” 
Merriam-Webster defines charity as “benevolent goodwill toward or love of humanity.” 
Taking all the science into consideration it is rather safe to say giving brings pleasure which leads to happiness.
That doesn’t mean run out and give whilly nilly. It means seek out ways to give and embrace the happy feelings in brings. Instead of running from charity, find a comfortable place for yourself and start there. Donate your time, give to the person behind you in line even if it is your spot in the line, you get the benefit of the giving. Keep in mind life is balance. And too much pleasure can lead to bad habits and traits. Staying authentic and true to your values you can be a part of the building while maintaining your health and happiness.