I just love it when the regular medical community stands idly by while things grow in you! Some malpractice suits ought to cure that. I spent 3 wks in the hospital recently, I had some little parasites trapped in my calves before the adventure began. As I laid in the hospital they grew up my thighs, scrotum, back, shoulders, and down my arms to my wrist. My skin was thickening behind them. I have some sort of filariasis, but nobody would listen. My LLMD, who is many miles away understands though. It is common, she says for the Lyme afflicted to have parasites of various forms because of Lyme's immuno suppression. Helminths, in general. Spleenic pain, I remember it well from 9th grade. When I tried to run track it would hurt and my lips would turn blue. I'm wondering how I've lived this long!
Lymph nodes are, from what I understand, swollen when your immune system has been fighting a bacterial infection (which Lyme is), because the job of the lymph system is to haul away all the trash left behind by your body fighting off and killing an infection. The lymphatic system is parallel to the blood stream, but the function of the lymph glands has to do not with taking nutrients to the cells in your body (as the blood does) but to transport other stuff.
If you go to wikipedia and look under 'lymphatic system', there is a sketch of the body and shows the spleen to the left side of the stomach, which is where you describe your particular pain. When the lymph system has been busy fighting off an infection, the spleen is the trash dump and gets enlarged ... so you called it! Too bad the first doc didn't catch that as signifying an infection.
It will be interesting to see what the blood tests show. Keep us posted!