If you were never HBsAg negative as far as you know, could you have been infected as a baby/child?
Tough one. Maybe an old roommate or something?
You may not know how you got it. Are you chronic? Genotyping might help narrow down the possibilities.
A nail salon could certainly be a source. I haven't been to one in years b/c I have serious concerns about the salon staff not taking proper precautions and I once saw them put away their tools after using them on me instead of sterilizing them. Now, they didn't cut me that day so there was no risk but it scared me. I wouldn't want to infect someone else.
Are you Asian? Been treated at a hospital?
No. I googled hep b and nail salons and read some interesting facts. I guess I will never know how I got it.
Do you have test results indicating that some time in your life you were HBsAg negative?
Nail clippers, possible, but low possibility.