Red MTG Deck Rate/suggestions?

You're going to find that the pheonix isn't just there to block flyers, it will be your primary damage dealing creature.

Secondly, you have 19 lands. And you're including some high CC creatures like Charmbreaker Devils and Valakut Fire Boar. Those cards really have no place in the deck in the first place, and really have no place if you're trying to run it on low mana.

Goblin tunneler really doesn't belong in the deck either. It's essentially worthless without kiln fiend, and it's just not a powerful enough combo to carry a dead card for. Replace it with another burn spell, you'll get the same effect without a dead card if you don't have a fiend out.

19 lands is not enough, you need at least 22-23.

Also not trying to split hairs, but it's creatures in MTG. Monsters is in yugioh.

i think it could work even though the other are talking about your only 19 land most of the time a red deck can run with as little as 3/4 land so 19 is and ok number. i also can see a way to put out Valakut Fire Boar and deal 5 damage in the first turn, hand would be 2 mountain 3 Rite of Flames 1 Grapeshot and 1 Valakut Fire Boar but a red deck will be ok with slightly less mana in my experience.

You may find Pyromancer's Ascension to be a bit of a dead card without a higher instant/sorcery count in a deck without blue spells to draw you more cards. I would play a few games with it in the deck, and if you can't get it active, either cut it or add a few more burn spells (Staggershock is pretty good with both that and Kiln Fiend). Also, you may find grapeshot and rite of flame a bit lackluster without easy ways to increase your storm count. Finally, your sideboard looks fine, but what those really come down to are what decks you expect to be playing against. Do those cards answer the cards you see most frequently? The one thing that I would point out is that I typically prefer Leyline of Punishment over Flaring Pain, since you can use it as a more permanent answer to damage prevention AND life gain.