can someone please explain to me the difference between PH and "mainstream". I am very interested in joining Freemasonry and have been for a few years but just became open about it this year because this year i decided its time for a difference in my life
"Mainstream" is used for lack of a designation such as PH (Prince Hall). We also sometimes call ourselves "Blue Lodge."
I'm at work and don't have the time to write an expansive history and explanation, but essentially, these are two different jurisdictions or "flavors" of Masonry. Both are ultimately descended from the old Grand Lodge of England (now United Grand Lodge of England or UGLE) and were founded around the time of the American Revolution, but Prince Hall lodges started out as Masonry for African-Americans at a time when they found little welcome into existing lodges -- primarily due to racism but also the previous membership of some members to Irish military lodges (as the Irish fought on the side of the British during the Revolution).
For a long time, both jurisdictions were segregated. As times have changed, so have attitudes and you'll now find members of all races in lodges of both. However, you'll still find a majority racial representation in each. As time goes forward, this will continue to become less and less so.
Whatever your heritage, I urge you to disregard the old divisions and check into lodges of both jurisdictions, joining the one you feel most comfortable in. As a brother, it's what's INSIDE that counts.