1)
Why does it say "Rabim Rodefai v'Tzarai"?
1.
Radak: Even so, I did not lean away from Your Edos.
2)
Why does it say "me'Edvosecha Lo Natisi"?
1.
Radak: His pursuers and afflicters sought evil for him, and he did not do seek their evil - "Lo Sikom v'Lo Sitor" (Vayikra 19:18), "Ki Sir'eh Chamor Sona'acha" (Shemos 23:5).
2.
Malbim: My pursuers and afflicters are many. The reason they pursue me is because I did not lean away from Your Edos.