If you go to the hospital for a check-up and they draw blood out and for a urine example would they let you know if you have an std? or something

Depends : They can only tell you if you are specifically tested for sexually transmitted diseases to begin with . They will test you only for what is clinically relevant as it pertains to your case . People are not randomly tested every time you get blood drawn or urine tested at any clinical facility .

Not necessarily: Depending on why you go to the ER.. If it's a non std related visit.. It is unlikely they will order tests to test for STDs. So in that case, no. Rarely are STDs considered an emergency department level concern and isn't routinely drawn on an emergent basis. If for some reason it is warranted and the hospital you are at can run the tests on site, they will give you those results there.

Check up: Hi, unless this subject has been discussed specifically it might not be checked. The doctor usually notifies you what s/he has ordered.