"Though" is like a shorter version of "although"
So where you would put "although" at the beginning of a sentence, "though" can be used at the end of the sentence, or even at the beginning.
Although I'm tired, I cannot sleep.
Though I'm tired, I cannot sleep.
I'm tired, I cannot sleep, though.
Note that although cannot come at the end of the sentence.
Also, bear in mind that it is quite informal to use "though" at the end of a sentence. In colloquial English, this is perfectly fine, but you would not use this in formal written messages.
- Sadia