Over the last 4 days I've been getting a constant ache in my right leg. It doesn't affect my joints (ie knee or hip) just my thigh, calf and the left side of my foot. It started about 3 inches above my knee and spread from there. Its similar to restless leg syndrome (I used to get that at night but haven't for years) but it's not just at night it's all the time. The exact spot the ache started I've developed a small black/blue bruise about the size of your thumb nail which I thought was a bit weird. Today I've started to get the same ache in my right arm also again not affecting the joints just in the top part of my arm towards my shoulder and just below the elbow.

(I've just moved and I'm between doctors so can't get into see them until my registation is complete.)

Could be anything from very minor to serious blood vessel problem, there's no way to know here.
A blood vessel break may not rise to the surface to be visible as a bruise for a few days.
Many doctors might tell an otherwise healthy person 'maybe you hit something on that leg/arm so let's wait and see.' You may have to protest if you are sure you didn't.
If you think you might have a tendency to blood clots or other vascular disease, or the pain gets worse, the doctor might order ultrasound or MRA. If your leg swells, go to an ER. Alert people around you to make you do these things if they see you space out or freeze (stroke): raise your arms over your head, smile, and talk.

It sounds like siatic pain... sometimes it radiates as far as the ankle,
Sometimes just the thigh... often the middle of your buttocks...
If it's in the calf you could be looking at anything from a charley horse
To a blood clot to phlebitis. See your internist to help you determine if
You need orthopedic or vascular physician. If it gets worse, take action
Soon