That sucks. I get a damn pump just leaning towards the mirror shaving. Picking up laundry. Doing dishes. Stuff like that.
I have had very similar problems with my lower back.
I have made significant improvements from incorporating,
Romanian Deadlifts and barbell hip thrusts into my work outs.
My lower back still isn’t perfect but it is 90% better after building these exercises up in weight.
I’ve come to the conclusion that it’s a combination of dehydration, and a forward tilted pelvis. To correct this, I’m attempting to focus on stronger lower back, and abdominal muscles. Also stretching my flexors. I’m working on my posture as well. I believe this all has to do with sitting too much, or at least for myself. Doing all of these things has definitely improved my low back pump, but hasn’t solved it completely. However, I believe with more time I’ll be able to resolve it. Unfortunately I drive 1.5 hours to work every morning, and 1.5 hours home. I sit for lunch and dinner. I sit through meetings, and I sit with my family to watch tv most evenings. It’s unfortunate, and I’m not always the best at keeping up with my core strength, or posture. I’m avidly working on it, and it is improving, but I feel I have a lot of work to do still.
Well I think I’ve finally figured it out!!! So for the last several months I’ve worked on staying hydrated, sitting less, strengthening my core, and stretching my flexors. While this helped, it never completely resolved the issue. So after my last post, I went to the gym the next day to hit my legs. I went in and talked myself out of doing it that day. Instead, I talked myself into running on the treadmill. After 20 minutes on the treadmill, I felt guilty and decided to do my leg workout. So I got off the treadmill and went straight to the squat rack. 3 sets of 8-10 reps @ 315 lbs, which is heavy for me, and NO BACK PUMP!!! Leg press, no back pump. Deadlifts, no back pump. After almost 2 hours in the gym, I walked out of the gym like a cripple. Lol. My legs were toast. I haven’t been able to hit my legs that hard for over 2 years now. I’ve done 4 more leg days after that, and I started each one with a 20 minute jog on the treadmill. Each time I get to the 175-185 calorie mark (just as a reference for my speed), and no back pump afterwards. I think that running for 20 minutes loosens me up really good, gets the blood flowing to my lower back and legs, and somehow cures my back pump. It’s incredible! Obviously this might not work for you, but give it a shot. I’m actually excited to do legs now. 