You are competitive for the majority of DO schools with your MCAT of 503 and your GPAs and ECs.
I suggest these schools:
TUNCOM
KCU-COM
ATSU (both schools)
VCOM (all 4 schools)
ACOM
WVSOM
NOVA
NYITCOM
Touro-NY
PCOM (all schools)
LECOM (all schools)
If you increase your MCAT to 507 or higher you could apply to some MD schools. Post your actual score here when available.