Totally anecdotal, but I took escitalopram (the first depression medication mentioned in the study) for years. It worked all right for a while but I was always very low on energy, and after a while it stopped working for me. After some trial and error my doctor and I landed on bupropion (which is also used for ADHD treatment) and it made an enormous difference. I would absolutely believe there is a lot of overlap in treating the two conditions, especially for helping with the the willpower/doing things side of the symptoms (e.g. having energy to do anything in the first place, completing tasks that need to get done, overcoming executive dysfunction, and not getting "stuck" in negative thought spirals).
But of course, it depends on each person and their kind of depression. My doctor warned me that it could make anxiety worse, for example, because the added focus and energy could feed right into someone's anxiety and make them feel mildly panicked all the time. It's highly individual.
Seconding this. A doctor showed me one stretch for the backs of my upper legs that got rid of my back pain. Follow the other advice here and see a doctor if it's bad, but leg stretches are free and easy so it's worth a try.
Stand on one leg and put your other leg up straight on a surface like a chair or bed so your legs are pointing at 6 and 3 on a clock. Keep your raised leg straight so your toes are pointing at the ceiling (not bent at the knee or twisted). Lean into it as much as you can while keeping both legs totally straight.
It doesn't seem like much of a stretch, but if it's hard to do, that may be your problem muscle group that's locked up and causing the pain.