I know this first hand. I remember that during lacrosse practice in high school I had to bend over and put my hands on my knees while we stood during practice. It wasn’t until PT school that I realized my tight hips were putting stress on my low back. If I hadn’t become a PT and fixed it, I’m sure I would have had lots of back problems by now.
The problem with tight hips is that they curve the back too much. The hips pull on the pelvis which pulls on the back. The back has a big curve and that puts stress on the low back and eventually causes arthritis which can lead to stenosis.
The short term fix is to stretch the hips and low back. The long term fix is to strengthen the core muscles. I would recommend that you get professional assistance with this. With the wrong technique or the wrong approach, it is easy to make the pain worse. With the right technique and the right approach, it is easy to make the pain better.
Back pain when standing is one of the easier forms of back pain to treat. If you have this type of pain, ask your doctor if you can see a physical therapist. Ask you physical therapist to check your hips.
Here is a video demonstration.