Ahh....yes , the infamous back pain! I usually get this about.....well I guess I have it all year when I boat. ANyways, what i was told to do, and what helped me was stretching your lower back by doing any stretching exercises that stretch your lower back, and glutes (your A$$). There are many ways of doing this, but one i find to help is by: sticking one leg out straight while sitting flat on the ground, then with the other like bend it in so it initially is like a half butterfly. Then lean over the bent leg and you should start feeling some stretching in your lower butt, and back....that helps me......
another thing is to have a girlfriend who likes to give back rubs, or a bank account that can support a chiropractor.
Just my 2 cents