Sources close to Mod Sun tell TMZ … he's moved on from Avril and has no interest in getting back with her.

Remember ... Mod Sun and Avril got engaged last year, but she dumped him and went public with Tyga in March -- a move Mod called a full blindside -- but, as we first reported, that whirlwind romance has now run its course.

However, Avril certainly isn't looking for a reconciliation either, as a source close to the star tells us, "Avril has been extremely busy working on new music and is excited about the future.  She has no intention of looking back at things that didn’t work for her previously."

While Mod Sun was initially devastated by Avril calling off their engagement, our sources say he's now in a good place in his life and doesn't want to get back with her.

In fact, Mod Sun is on the European leg of his tour, where he's teasing some new songs inspired by his breakup with Avril.

We're told the rocker used his pain to create new music, and he refuses to let himself go down a road of hurt and lies again.

As for Avril ... TMZ broke the story, she and Tyga split after a few months together -- but our sources are adamant -- the two remain super close friends and both are working in the studio separately on new music.