Thank you for your query at DoctorSpring.com
I understand your concern and I appreciate how you have fought through the intense pain that you were subjected to after your injury.
The lower ribs ( mostly from the 7th- 10th ) are prone to fracture and can present with intense pain. Since you're feeling a swelling it needs to be clinically examined now to rule out a diaphragmatic hernia. Such injuries have the propensity to injure diaphragm leading to a hernia. Splenic rupture is an emergency and does not look likely here. The symptoms in a splenic rupture are intense pain in the epigastric region and the left flank, giddiness and loss of consciousness due to hypovolemia which developed rapidly following ruptured spleen, and sometimes a referred pain in the left shoulder.
However, splenic injury can't be ruled out with mild enlargement of the spleen.
So kindly get yourself examined and you definitely need a CT SCAN of your abdomen for a conclusive diagnosis.
Please feel free to discuss further,