Because breathing is more difficult when you injure your intercostal muscles, smoking will worsen your issues with respiration. If possible, stop smoking and avoid environments where you might encounter second-hand smoke. While compression is usually advised for some sprains and strains, that’s not the case with your intercostal muscles because it makes it harder to breathe (per Spine-Health).
When you’ve strained your intercostal muscles, your breathing can become shallow. Shallow breathing can lead to complications such as pneumonia or other infections. While you’re still recuperating from an intercostal muscle strain, you’ll need to work on deepening your breath and expanding your lungs for a few minutes every hour. Deep breathing exercises where you hold your breath for 10 seconds will prevent respiratory complications (per Healthline).
Even if you start feeling better after a few days, it’s not such a great idea to return to activity. You run the risk of re-injuring yourself because these muscles are still weak (per Spine-Health).