Absolutely not, under any circumstances. You will get very sick and/or die. NEVER EVER shoot plant matter. Even kratom extracts have too much plant material left in them for IV use.
Even if you could IV it, the dosage is at least a few grams of leaf so I don't see how you could make it concentrated enough to shoot. But again, do not even consider trying because you'll die.
Kratom doesn't feel like heroin at all. If you're expecting it to feel like classic opioids, you'll be disappointed. It's quite nice if you have very little opiate experience. It's decent if you have opiate experience, and if you have an opiate habit currently, you will not get you high, but it does keep away withdrawals.
If you get your hands on strong, good quality extracts, it can feel a good bit like oxy, but it's very expensive that way. It's really just not possible to get to that level with plain leaf, as you reach a ceiling effect where you start to get dizzy/nauseous before you can get higher.
And again, even with extracts, do not even think about injecting it because you will end up with life threatening infections in the best case scenario.