Rosehip,
I had a spleen injury in the form of a cyst on the spleen a couple of years ago (though I don't know exactly how I received it). The pain I felt from my spleen was actually referred pain up to my left shoulder. My abdomen didn't really hurt until the cyst on my spleen was quite large (1 liter of fluid was drained out).
When I would poke a finger under my ribcage where the spleen was located, it hurt in my left shoulder. When i laid flat, you could see that the left side of my rib cage was higher than the other.
The most noticeable symptom for me was how hard it was to breathe deep. A deep breath brought sharp pain up to the shoulder.
I'm not a doctor and things are different with everyone, but your injury doesn't sound like a spleen injury.