
It does sound as though she's in pain. I'd go for the x-rays - better to know what you're dealing with so you can treat her the best way possible.
It may be that she needs medication to manage it, but there are also a lot of natural remedies that can be just as (if not more) effective than conventional meds, it just involves a bit of trial and error. Turmeric for example is an excellent natural anti-inflammatory, and has been much better than any drugs for a couple of my dogs; it also helps soothe the gut so could perhaps be of benefit for Pip that way too. I use it to help one of my dogs get over the odd bout of colitis.
Then there's the more typical stuff - glucosamine, chondroitin, MSM, fish oil - or other stuff along the lines of turmeric, such as coconut oil, devil's claw, shark cartilage, hyalauronic acid, bromelain (which can help boost the effects of turmeric if given together) and so on. One of mine barely responds to anything except PLT (conventional drug) but I have to be careful because she's prone to colitis; but with a combination of raw meat/fish and rice, devil's claw and coconut oil, she is almost pain-free and her arthritis is absolutely awful.
Exercise-wise I'm afraid that the best way forward with arthritis, if it is that, is little and often - shorter walks but more of them, and doing it that way can actually improve the condition as well as preventing it getting worse through overwalking.