Is there any real doctor out there to give some advice?
It could be anything from a strained muscle to pleurisy. A proper medical examination is required.
Never take medical advice from some random stranger like me, but it does sounds like pleuracy by the symptoms you're describing. Pleuracy can be very uncomfortable but is usually not series in itself. There are some possible underlying causes that may be more serious but it can be triggered by onset of a common cold or possibly fighting off some minor infection - if so it may resolve in a day or so. A doctor would want to take some images to rule out pneumonia, partial collapse/pneumothorax.
Sophie is a neurotic hypochondriac who's always posting crap like this. She comes up with a new problem every few days, listing ever more vague & obscure symptoms, then rails at people who tell her to 'Go see a doctor.' She's a genuine nutter.
Yes, because doctors love to spend time giving out free advice on a second rate social media site after a long day of having diseased ridden people and hypochondriacs cough in their face.