Would I be able to tell if my spleen had ruptured?

Usually. A ruptured spleen will usually cause internal bleeding within the abdominal cavity, which is quite painful and hard to miss. On occasion, there may be a contained rupture that does not cause immediate symptoms; this would be seen by ct scan even in the absence of symptoms.
No. Generally little discomfort with that- just severe bleeding that can cause problems. See your doctor if you are worried.