Heart and brain problem. My thinking?

My heart use to pain when I stand and sometimes suddenly it starts ,it last until I changed my position . Few time my head also becomes blank it took me some time to make it stable . And also my head use to pain alot sometimes . And few time I can't stank properly it's like my head at that moment complete becomes blank and I couldn't even stand at that moment at that time I need to stick to something like wall for getting support . I haven't told this to my parents because their are already lots of problems here I don't want to make them have more problems . it's now had become a month since these all started appearing .If this a disease or problem which require medical attention then I will tell them . Is it any disease ? Or it's just my thinking ? Please help me Thank you