There's the possibility of stress fractures from a high impact sport (depending how hard you ride) and maybe a prev fracture - you tend to know if you have broken your fibula but as it doesn't take most of the weight in the leg if you a tough guy you may have broken it without realising it was broken. So Get an X-ray to rule those things out!
Everything you mentioned could be possible causes of pain, it could be muscular (prob more likely than a break)
Sounds like you better go get a physio appointment for further assessment there buddy.