Is it okay to have mild pains in my left side? i dont know for a fact that my spleen is swollen but i was diagnosed with mono 2 weeks ago.

Pain can happen: If you have mono & If your spleen is involved ... It might swell and stretch the splenic capsule causing pain. The spleen also might break open and bleed in worst cases. Although mono sounds like a reasonable explanation of your pain, please stay in close contact with your doctor to keep tabs on this.

Okay if it's mild: You could have abdominal pain. As long as it's mild, it is okay. I suggest avoiding any contact sport or strenuous exercise If the pain worsens have it checked out.