Burning sensation in lower legs

I was diagnosed with CREST syndrome about 6 years ago, though the symptoms started about a year before that. Recently, I started having pain in my knees and hips; my rheumatologist has been unable to identify the cause. Then, about 3 months ago I felt a sharp pain in one of my calves, which went away after a day, and a few weeks ago I started having a burning sensation in my lower legs. Has anyone else experienced this?