How can you get your 'uncommunicative' boyfriend to talk about his feelings and emotional issues when he finds it very difficult to open up and it is killing your relationship?

A common source of contention between some men and some women is the issue that you just described. Many men just don't like to talk about feelings and emotional issues yet somehow women who "hook up" with them seem to think that they can change that part of their man. If he isn't what you want, go find someone else. If he is someone that you care for, don't try to change him. For the first 20 years of our lives boys and young men are taught that they shouldn't cry, shouldn't express their feelings, "Be a man" usually means to keep our mouth shut about an issue. Couple that with the fact that women tend to bond by "talking", and men tend to bond by sharing experiences it's a wonder that men and women ever get along. Men can be quite content to go fishing, not say a word to their buddy and when they get back they're quite content if the most they've said is "Hey! Look at the size of that BASS!" Women tend to want to talk about things far more than do men. Like him for who he is and don't try to change him.