Seems like this conversation has come full circle. COTM , I felt exactly like you for practically my whole life. Your questions lie rooted in emotional pain.
There are many things that people do to not feel , or can change , the way they feel.
Did you ever think that you could have some control over your emotions ?
It's my own view that you can have some control over those emotions that come about from " outside you " , ergo , the physical world. And also that come from within. It's all about how your " wired". The only reason we feel anything is because of our physical body. For example, if you had a lobotomy or were dead
you wouldn't feel a damn thing. Now some examples of how you can change your feelings have already been mentioned , . You do have the ability to do it if you know how, period.As to your original question, why feel at all , that's a philosophical question, or religious, or whatever. The reason, in my belief, has already been said. It's what makes us human. And remember , this universe is made up of opposites working together. Plus and minuses, yang and yang. Without the bad , we wouldn't know the good. When you start feeling some good in your life , you will " feel " better.