Can't reach 3 hours between pumps.

I am 3 weeks postpartum. I am working towards pumping every 3 hours. I started at every 2 hours, 15 minutes per boob. I naively slept through my 2nd and 4th night pp and woke with the rockiest of rock boobs. Completely traumatised me.

I have been gradually increasing by 15 mins after 2-3 days. And I always hit a roadblock (read: milk "block") at about 2h30 to 2h45.

I start getting really sore, heavy and painful. I currently have a huge lump above my right boob. I can also feel the tingles under my left boob but almost negligible compared to the one on the right.

There is so much conflicting advice around. Pump more, don't pump more. Pump only one side, ignore the painful side.

How can I reach my goal of pumping every 3 hours smoothly? What am I doing wrong?

I am hesitant to visit a medical professional, unless absolutely necessary since at the hospital when I delivered I was already given conflicting advice. TIA!