White dots/spots on nails. Problem?

First pic is of my left thumbnail and second is of my right middle finger. As you can see in pics that I have marked white very small dots/spots on my nails. I am having these from year end of 2020..and they are not going. I cut my nails hoping to see that the spots will grow out and they do.. But new white dots keeping coming back from bottom of nail in same line.. It's like in loop. They keep growing out and new ones come in their place in same vertical line. I searched about white spots and It showed me Leukonychia.. Which looks totally different from what i have.. My white spots/dots are small and almost pinsized and they grow out in one vertical line/ridge of my nail and they keep coming back on same line/ridge... So what is this? Why are these dots/spots that keeps coming back again and again in very same vertical line? Why do i have these? Is this something serious? Is it any symptom of serious problem? Please tell me.. I have been anxious about this for 2 years.