Can i get myself checked for any diseases without my parents ?

Excellent question: Yes for sexually transmitted diseases. Many young people defer being tested, uncomfortable bringing this subject up with parents. Per my research on the Internet. All 50 states and DC explicitly allow minors to consent to testing for Sexually Transmitted infections without parental consent depending: Go to The Guttamacher Institute; which has a state by state breakdown of the laws affecting minors

Yes: Most states permit minors to be evaluated and treated for any illness related to sexual health without an accompanying parent or guardian. This generally includes screening/treatment for sexually transmitted infections including HIV, and it often includes visits for contraception. Different states have different laws though; your local health department will have more information.