I was treated for p.I.D should I have any other tests done? I read somewhere that mucus or something can form around the ovaries?

Infections. Infections travel in pack...When you are diagnosed with one, I recommend getting tested for all of the common sexually transmitted infections (syphillis, hiv, gonorrhea, chlamydia, trichomonas, and sometimes even hepatitis). You want to know everything is clear! Get your partner tested/treated as well....And be safe in the future.
PID. Sometimes scar tissue can form around the tubes and ovaries. Any type of inflamation in the belly leads to more or less scar formation. Make sure you get another ultrasound in 6-8 wks after finishing treatment to make sure you are not developing complications of tubes called hydrosalpinx.