Dear you have not mentioned the age the your boyfriend . As described by you it seems that he has he has palpitations . This may be because of anemia hyperthyroidism anxiety excessive drinking of caffeine containing drinks alcohol certain drugs or with the problem in heart.every other thing can be find out very easily by complete history and physical examination and if needed some blood test ..and these can be managed also very well.but if it is originating in heart it should be diagnosed early and managed properly.for that ecg that will record electrical activity of heart is done..If needed Holter monitoring that you can understand as continuous ecg is to be done . echocardiography will take images of heart to rule out any structural cause associated with it.at this time I would I like to suggest you that you discus these things with him and make him understand that there are few very common causes such as alcohol but few needs attention . So its very important that he should discuss all this with physician and get appropriately worked out to find exact cause.hope this will help.