Thanks, Merry! Well, it's a long story, I swear I tried to make it short.

My SOB started 1.5 months ago, but the whole story dates back to February when I started having chilblains on my toes.
Then I had a cold, and another, and another, and in March I ended up sitting on my couch, coughing for a week, having low fever, and unable to take a deep breath or yawn. I also made a wheezing sound when I exhaled deeply or after coughing. I was prescribed antibiotics (clarithromycin), and the next day I started coughing up a lot of mucus, my nose started clearing up and overall I felt better. My SOB disappeared basically the next day I took the first pill.

On the 4th day, however, I started having pain in my right ribs, just below my breast. It felt like pleurisy, breathing, and coughing was painful, so on the 7th day, I visited my GP for help. He didn't even listen to me or to my chest (he was afraid of COVID so he tried not to get close to me), he just prescribed me another pack of antibiotics (moxifloxacin) which I then took for an additional 6 days. I got slightly better, and I stopped it because a pulmonologist who was willing to examine me and told me it might be just muscle pain, and my x-ray was clear. The side effect of moxifloxacin was a slight stabbing sensation in my heart, especially when I laid on my back. It went away immediately when I stopped it.

I still kept coughing lightly, I suspect that because of the pain I couldn't excrete the leftover mucus from my lungs. I also kept sleeping on my right side, because then it didn't move when breathing, leaving me without pain.
I started getting better, started working again (meaning bending over to the computer and stressing out because I was waaaay behind my work). I also started lightly exercising and restarted cycling.
Then while massaging some cream to my ribs, I found little pea-sized, painful nodes in my breasts. The next day they got inflamed. It lasted for two weeks, and after the inflammation went away, the nodes cleared as well. I suspect they were swollen lymph nodes, but never checked with a doctor. Almost immediately after it was gone, came my SOB in mid-April with temperature (37 Celsius), shaking, and lightheadedness.

Then I had COVID-19 test (negative), I've seen the pulmonologist again, who found my lungs okay by listening and prescribed me antibiotics because she suspected I had tonsilitis. Strangely I didn't have a significant sore throat, but my neck was very stiff and my tonsils were swollen. I got antibiotics (clarithromycin again). By the end of the course, my SOB improved a bit, but I saw no change in my tonsils.
I visited an ENT, she said I have no acute tonsil inflammation. She also asked for a pollen allergy test and head CT, all came out normal.
Then SOB got worse again. I had bacterial culturing from my throat, nothing was found.
Nevertheless, I got another pack of antibiotics from my GP (metronidazole) for anaerobic bacteria. It helped with my stuffy nose and the tonsils also got smaller, but my lymph nodes got swollen on my neck and my stomach got very upset. I was nauseous even by thinking of eating and having a terrible headache. I only managed to take it for 4 days.
Then my GP prescribed antifungal medicine, antacid, and asked for a blood test.

My blood test came out normal, indicating I don't have any inflammation.
Only a couple of values were out of the acceptable range:
ASO was high, but it was around the same level 2.5 years ago. 4 years ago I had streptococcus infection, another ENT told me it can remain elevated for years.
TSH was higher than ever (4.35), and T4 was low, just in the acceptable range, suggesting hypothyroidism.
The antacid helped me with my stomach, now it's at the level where it was at the beginning.
I stopped taking the antifungal.

My SOB started getting better since I started neck exercises and changed my preferred side of sleeping, and it gets worse when I'm bending over to the computer. Not sure, though, because of the position or because of the stress I'm having during work.
Feeling cold also makes it worse, and I'm usually shaking. I'm also wondering if hypothyroidism can cause SOB, or at least make it worse.

I was also examined by a rheumatologist, and she didn't find anything which could've caused my SOB, though 2 days after I started having pain in a specific point in my left rib (I think it's the second rib), between my collar bone and breast. Also, pain radiates to my left hand.
And here I am now, not sure, where to go to. I'm thinking of a cardiologist to make sure my heart is not to be blamed (I have palpitations and low blood pressure), also would like to rule out all lung issues by having a chest CT. I'll also consult with a GI next week because of possible reflux. I'm still taking the antacids, though. All doctors told me my tonsil problem could have been caused by reflux, even though I don't feel it. And everyone, except for the ENTs believes that my tonsils are to be blamed for my SOB.

Good news that my SOB got better by now, and I started coughing up some phlegm again.

Thank you for reading it, and please let me know if you have any suggestions.