I had this trouble when I first had my ears pierced. Especially with a new piercing, it doesn't take much to cause a problem. It really does take years for the piercing to get sufficiently scarred enough to be fairly well protected from this.
I had studs to begin with, with the little catch along the shaft to stop the back bit from pinching up too close to the ear. I found that if ever it DOES pinch up, my ears get sore and inflamed. And plastic backs don't lock on properly, even to an earring shaft with a catch on it. By 'catch" I mean that little notch effect, like a ring around the earring shaft which allows the back to settle in place.
I got my ears pierced while recuperating from kidney surgery, I was living with my parents at a tropical beach and swimming every day to regain my strength. I had long hair also, and I found a hair (more than one) would get wrapped around the earring shaft at the back. I remember husband (he was on holiday at our beach with his parents) found a hair and unravelled it, he said the end of the hair had actually gone inside the hole in my ear. And yes, that ear got infected, but keeping the hair away from my ears (I tied it up into a bun after that) and keeping the catch from locking up hard against my ear, helped it heal.
easy child went through a similar thing - plus, I found that apart from my stud sleepers (the ones which were used to pierce my ears) if I wore ANY stud earrings, my ears would fairly quickly get inflamed. Even pure silver or gold studs would upset my ears after about a day. Sleeping in studs really upsets my ears.
So I went out and bought myself a pair of sterling silver sleepers - the ring type. I wear them constantly. I can thread ornaments on them if I want - an alternative to dressy earrings. Of course, my skin turns sterling silver black, but I don't care. Dangly things scrape the black off and they still look OK. If I want to wear dressy earrings then I do, but I carry my sleepers so I can put them on when the outing is finished. I keep them in a small box in my bag so I can change out of my dress earrings and put my rings back in when I'm ready to sleep for the night. MUCH more comfortable. And infections are now VERY rare. If I get one, the rings make it much easier to treat. I dab on hydrogen peroxide rather than alcohol, followed by ti-tree oil. And I spin the ring in my ear lobe to get the treatment into the tissues where it needs to go.
If the hole begins to close over you can open it gently by putting in some thinner earrings (avoid any metal other than silver, gold or maybe surgical steel) and then gently wriggling the ring around to stretch things comfortably. Sleepers tend to be much thicker, I put them in last. If the ear is inflamed, the original sleeper may not go in without doing more damage, but the rings tend to be thinner and easier to manage. Simply having even a really thin ring in, can open the ear up PLUS let the inflammation settle, so the next sleeper attempt should be easier.
I have at times left earrings out for months. Not good. But I got the hole to open up again using that technique. And with an inflamed ear, a ring sleeper should still be OK - it allows the ear to 'breathe' and still keeps the hole open.
The doctor told easy child, when she got her second pair of holes, that the further up the ear lobe you go with piercings, the greater the infection risk. He told her to never get any more ear piercings, she was already getting too many infections in the new holes.
Hope that helps.
Marg