I've been spray painting a prop for only about 5 minutes and I think I breathed in some fumes. Now I'm feeling this tightness in my lungs and there's a dull pain on my right side that I've had for a few days. I read it might be lung inflammation that'll go away by itself. Should I be worried about this?

It's natural to feel concerned. Short-term lung irritation from spray paint fumes often subsides with time, especially if you're now in fresh air and staying hydrated. However, if the tightness or pain worsens, or you notice symptoms like wheezing or breathlessness, consult a doctor promptly.