I've been having lower back pain when I walk for about more than 10 minutes. If I sit down, it alleviates the pain, it disappears, but as soon as I start walking again, after about five minutes, the pain comes back. I usually walk a bit, rest, and then continue walking. I just walked a 2.2 mile trail and I had to rest about 4-5 times. The pain goes away pretty instantly when I sit down, but comes back quickly? Is it inflammation?