Hi.
First of all be sure u did not have a fall. Chances of any fracture are rare at this age unless u r osteoporotic...
Next Steps
in case u had a fall or hit... get an x-ray chest done .. if it does not shows any fracture... u have possibly strained your intecostal muscles. check for any pain area in case u can pin point any on pressing. if yes.. do contrast treatment... put heat for 5 mins and immediately apply ice for 5 mins( be careful ice also creates burns...so keep checking) on that area..
Health Tips
use rib belt... u can get it from any surgical store.. it will help u easing pain while turning in bed and getting up..