"Tho" is not really a word, people seem to use it in text messages to reduce the message length so they can say more with less letters, and what they really mean is "though". So yes, "tho" = "though", but it's slang only really appropriate on electronic communication where it's necessary to shorten the message.

"Tho" is the informal spelling of "though". I wouldn't recommend you use it in anything other than, perhaps, a chat with friends.

Tho is more of a slang, so if you wanna be formal while typing, you use though, as where you could use 'tho' in an everyday conversation with friends. There's not much of a difference between the two, except for what I've mentioned. They mean the same.