For the last year or so I've been taking the deadlift seriously. Every time I near my max, we'll say my 3-rep max, I feel a what can best be described as a pressure / pain on my lower rib cage. It feels like it could be deep muscle, as the pain fades quickly (1 or 2 seconds) after I set the weight down. Anyone else experience this? Anyone know the cause/how to remedy it? Thanks.
This may be an indication of an imbalance in the supporting muscles. Namely, the core and posterior chain. You might consider some accessory work on your core and lower back to bring them up to speed with your DLs.
Deadlifting is a great exercise, but without understanding what else you are doing I'm going to be working off of assumptions.
However, before I get into that, have you ever had chicken pox? Last year, it felt like I strained my back, only to find out it was shingles. A combination of getting sick and training hard for competition depressed my immune system enough that I had a flare-up of shingles. Before that after heavy 90+% pulls the same area felt like it was on the verge of a strain. Anyone who has had chicken pox potentially has the shingles virus waiting for your immune system to get depressed enough to let it cause pain.
If you are not dealing with shingles, and have never had the chicken pox, then you may be dealing with a minor lat strain. If you suspect this is the case, then my recommendation is:
Low-weight, high rep work helps get blood flowing through the affected area which speeds recovery. While pull ups are great at working the lats, they will likely be too heavy to get the work you want done. Potential lat exercises can be:
You can use any of several alternatives, but you want to work with a weight you can do 3x15 (3 sets of 15 reps each). Feel free to drop 5-10lbs each set if necessary to keep the rep work going. If one variation of exercise causes the pain or makes it get worse, choose a different alternative or lower the weight.
Do the lat work every time you are in the gym and try to increase the weight no more often than weekly. After 2 weeks of this, you can start to slowly increase the weight on the deadlifts--staying below the weights that cause pain. By the end of 6 weeks you can taper the lat work down to only being done after deadlifts. By that time you will have built up the work capacity of your lats and repaired the strain.
I recommend that even after the 6 week rehab work is done, you don't just jump right in to 90+% work on the deadlift again. Build up from 80-90% again.