Severe, short-term, quad pain shortly into ride after 3/4 days off

Let me start by saying, I'm not looking for a diagnosis, or cure, just wondering if anyone has experienced anything similar.

I'm fairly regular on the bike, 3-5 days as week, would probably average 150-200k per week. My problem is that anytime I've had more than a couple of days off the bike and then gone out for a ride, I've experienced severe, really sore, pains in my quads shortly into it, which remain until I finish and rest.

This morning I went out for a short spin after being off the bike for a week due to some kind of bug (feel fine now, it's not related). After about 3k, I started getting the pain in my hamstring (this is a first), so dramatically cut my effort. Then, the quad pain arrived, so sore I had to keep stopping every couple of k and have a rest before continuing.

Now, 20 minutes after arriving home, I still have the pain, but I know from experience it will subside later today and if I were to go out tomorrow, there's a good chance I'll have a flash of pain in my quads from time to time, but otherwise will be normal and won't experience this until the next time I'm off the bike for a while.

I found this
http://forum.cyclingnews.com/showthread.php?t=16610 on the cyclingnews forum, which sounds similar to my issue.

So my question - has anyone else experienced this? Is my best bet to go to a physio (I did mention it to a physio before who didn't seem to know anything about it), masseur or start with my GP?

Edit: a couple of points to add:
1. I experienced this before when I first began doing significanlty more kms than I'd ever done before - it resolved when I changed my bike
2. I did go to a chiropractor, around the same time. IMO, the bike change was the resolving factor.
3. I am very bad at pre- and post-ride stretching.