I have an 11 week old yellow labrador his nose is half pink and half brown is that normal

Don't look for problems where there aren't any. Yes, its normal for his nose to half and half and that may change to all black as he gets older.

Tick

Yes all dogs have there own couler it like humans we have differint things

Apparently yellow labs with brown or pink noses are called dudleys. They are perfectly normal just not show standard.