Try going outside and see if the symptoms resolve

I recently had carbon monoxide poisoning from a gas leak and I didn't have a burning or sore throat, but I did have all of the other symptoms you've listed. Headaches, dizziness, chest pain when coughing (also increased coughing) and fatigue were the biggest things that I noticed, alongside my body just feeling really weak and fragile. Idk what circumstances you're in though so it may not be exactly the same as mine, as the boiler in my bedroom was leaking gas over weeks and built up until I was really unwell. It usually depends how long you are inside the room with a gas leak and how much you inhaled. I hope you're okay and not still in the room affected!

if you think you might have a gas leak, leave the space and go to a well-ventilated area (ideally outside) for at least 20 min. If you feel noticeably better, there is likely a gas leak. Briefly go back in and see if you can identify a distinct smell. Flammable gasses are mixed with strong odors to help identify potential danger. If you do smell an odor, leave the building and do not use any lights on the way out. If you do think you have a gas leak, even if it is not a flammable gas, you should call 911 or your local utilities maintenance if you have one .