How many trunks does it have right now? Does it look like it might have been grafted, as is probably likely?

Immediately after I posted your pictures appeared. Your tree is grafted and those are rootstock sprouts that need to be removed.

if you had bare rooted the tree at planting.. you would know what is going on down there.. but i suspect i agree with embo ...

did you select this tree.. or was it installed ... i would not have chosen one with that grafting cut ... i would have wanted one that had the understock removed when the plant was very young .. and the graft already healed over ... perhaps a lesson for net time you buy a tree ...

which now makes me wonder where the root flare is.. as who graft one inch above the soil??? .. can you gently scratch around in the first few inches of soil.. and find the root flare ... this is what you are looking for

https://duckduckgo.com/?t=ffcm&q=root+flare&iax=images&ia=images

and if if significantly buried .... then this might be what bothering you in terms of something wrong ...

ken