I hurt my ribs playing soccer (body on body collision).  My ribs were sore/tender for a couple days.  On the third day, my ribs cracked when i was stretching in the spot that was sore.  It hurt like hell and now hurts more than it did after the first couple days of the initial injury.  I have no problems breathing or excercising, but it really hurts when i get up out of bed or try to do any ab excercises.
Dear friend. I have gone through your question. Pain in ribs which is increasing in character is a matter of concern. It can be a contusion of skin and subcutaneous tissue which is causing you the pain. It can also be a minor hairline fracture in the ribs which is causing the pain(as you have mentioned cracking) and increasing pain. As there is no breathing difficulty, the pleura underlying the ribs is not injured it seems. Since the ribs enclose the vital organs in our body it is always better to get a chest X-ray done to rule out any major injuries.Also, you have to take adequate rest and analgesics for pain relief and faster recovery. Thank you.