I went for a very big walk up in the mountains a week ago - only 6 miles but about 3,000ft of ascent. Since then I have had problems running - hip flexors a and ligaments and muscles around knees are sore and stiff although I wouldn't really call it joint pain as it doesn't feel like it's the actual joints that are a problem. Not sure whether to rest or keep going. I've kept going up to now but my legs have been very stiff. I'm loathed to stop running as my fitness is really improving.