Hi,
Pitru Dosha is supposed to be associated with Karmic debt of your ancestors, involving their past misdeeds, an indication of unsettled souls, or wrong actions in their lives. Please consider a quick/simple Google search, to get some understanding of Pitru Dosha.
If my understanding is right, this has been affecting multiple aspects of your life – including marriage, quality of and success in life, career growth, accomplishments etc. So, you would be better off addressing the same with appropriate Vedic/Dharmic remedial measures, on priority basis.
Take care…