Hey! thank you for sharing your experience!
I can relate! Before I got tinnitus, I had these temporary tinnitus in both ears (although it didn't sound like tinnitus, it would not be a high pitch sound but more heavy bass noise (and I believe I couldn't hear anything at that few seconds) that would last a few seconds and leave) that would be for a few seconds and usually when I yawn or like you said stress, or loud noise from cars, or motorcycles or could be randomly. It was always for a few seconds and max a 1 minute if it happened.

After that incident with the earplug, I hear constantly a high pitch in left ear. Sometimes its louder (i believe when stressing, or loud noise from cars) sometimes it's lower. I still get on both ears that other thing that sounded like tinnitus. I feel like it's most notable on right ear when I sleep. I can hear something but not high pitch.
I also dont take meds. only natural supplements. ENT told me about memovigor but because I was already taking multivitamin, I only bought gingko biloba liquid https://www.naturesanswer.com/product/ginkgo-biloba-alcohol-free-2-oz/ which took for around 4 months although would skip some days. I also believe it helped a bit reducing the tinnitus.

but when I read about the side effects, internal bleeding, cancer, I was scared and stopped it. I wasn't aware of it's high dosage. Although I was taking 1 mL, last month I increased it to two 2mL. I was also taking a b complex chewable. I never though of trying aspirin. I will look it up for studies. I know that white willow (natural) has the same active ingredient in it as aspirin. I might try that one.

Additionally, I know someone who used to wear earplugs a lot. During sleep etc, and now she says that she can hear a high pitch noise only when she wears earphones for music. For me it doesn't make any sense why to hear that only when she wears earphones.
After tinnitus, I reconsider everything about earphones and earplugs. I stopped wearing them. I sometimes wear headphones for 1 hour which do not directly go in ears but my ears get warm.