Screen doesn't work properly - iPhone SE

I have an iPhone SE in almost perfect conditions (I never dropped it). I bought it 9 months ago, but since 3 weeks (and maybe more) the touch screen don't always works, I mean that when I touch, sometimes it doesn't understand that I'm touching, and that's very very annoying. The problem happened at least 1 time per hours and I already tried to clean the screen and restart my iPhone, do you have any ideas?