Hi,
Pitra dosha comes when sradham is not done to ancestors. If you father or grand father is alive, they are supposed to sradham. If you fail then the problem will arise.
There are 7 sthalams for performing the rituals (Pindam,Tharpanam) for dead(pithru sthalam).They are Kasi,Rameswaram,Sri Vanjiyam,Thiruvenkadu,gaya,Thiriveni sangamam
the seventh one being Thilatharpanapuri, kumbakkonam, tamilnadu. In Ramayan, When Ravana took Sita, Jatayu tried stopping him but finally killed by Ravana.During the return from Lanka, Rama and
Lakshmana did the rituals for their Father and beloved Jatayu as well.
Also donate food to the needy during amavasya