Welcome @semaj, I have idiopathic small fiber peripheral neuropathy and do have some additional discomfort if I'm sitting down for long periods of time. Also, when I sleep I generally use a small pillow between my legs when sleeping on my side due to some discomfort in my legs. While you wait for other members with similar experience to respond, you might find it helpful to scan through the comments from other members with similar symptoms. Here's a link of the search results for "leg pain sitting or laying down" - https://connect.mayoclinic.org/search/comments/?search=leg%20pain%20%20sitting%20or%20laying%20down.

From what you describe as your symptoms, I think there are possibly many different causes. Have you discussed your symptoms with a doctor or had any tests?