Being Bipolar does not mean one lies, one's lieing cannot and should not be blamed on mental disorders. Yes, one can be Bipolar, and tell lies and just the opposite.
People without any DXes lie and some don't.
Perhaps, a counselar can help you find the source of why you tell lies, it could very well be something stemming from childhood, a defense mechanism, or something that developed later in life. So many things can be behind this, sometimes a therapist can help you zero in on the reason and/or causes, and then will try to show you how to get away from lieing.
I hope you'll be able to find help, which in time will help you be at peace with yourself.
Take care