Hi, putting your mind at rest is very important. Keep in mind that you are young and even though heart disease runs in your family, it sounds as if it wasn't a problem when your relatives were your age. You have an advantage of todays advances in medicine and the knowledge that you can take steps, now, to lower your chances of following in your parents and grandparents footsteps.
The heart palpitations are usually benign events. I've had them for 30 years and periodically run to the doctor when they get really bothersome. He runs some tests, I wear a holter monitor and the result is always the same. "Benign, don't worry, go home and deal with them, most people have them, you just have the honor of feeling them, etc." Even after 30 years, they still freak me out.....I think we all agree that we hate them, but we have to live with them. Again, if you can, check with your doctor to make sure in your mind that there is nothing wrong.
As for the twitches, you mentioned that they happen when you are are using your hands and that they worsen when you are nervous. I've been there and done that.....it could be related to anxiety or panic. Your body will do some really weird things when you are worried, stressed or just plain scared. Same goes for the eye hurting. Could be that the cough sets off a nerve impulse that zings its way to the eye. I've got a crappy nerve situation that flares up periodically and causes so much pain in my front teeth that I just about howl, can't eat, can't talk, etc. I had it checked out to set my mind at rest, at least I have a name for it now and know what it is.
Please check with a doctor and discuss your concerns. He/she will be able to give you advice, set your mind at rest and suggest life style changes to help you stay healthy. Take care, you are not alone in these feelings and experiences and have found a great place to talk with others who are dealing with the same things.
Hey, chances are they are not a big deal. However, you should get tested just to put your mind at ease. The family history of heart disease in your family makes it even more of a reason to get tests done just to make sure. I have had these things for 10 years and I run and lift weights and play basketball all the time. Don't get me wrong they scare the hell out of me every time I get them. I don't have the insurance to get testing done now, although I did do many tests years ago that all came back normal. They are very common and from what I hear from most medical people they are very often benign. I'm nothing close to a doctor but I'm just giving you what I know from a lot of research and talking to others who suffer with these problems. I have no idea about the twitching being related but I doubt it very much.