I don't know what kind of Hei Gung you practice, but external work has a more pronounced "cold phase", as you say, while internal work can minimize it appreciably...
Some people believe that eating soup stock made from joints, bones and cartilage is important for our own self-maintenance and repair, yet others swear by Glucosamine with Chondroitin...
IMHO Laukarfei's advice about seeing a professional about it might be best, before some situation worsens or becomes chronic. Still, I don't agree about "many Gung Fu people punching wind" as holding any water, if done correctly (no repetitive hyperextension or excessive weight). Certainly less problematic than incorrect bagwork, or wracking up your knuckles, wrists, toes and ankles on your sparring partner's elbows, shins and knees, let alone getting twisted up in matwork on any kind of ongoing basis...
Besides, what's with such characterization about Gung Fu in the first place? Maybe HE learned HIS like that, but I'm sure that's another story altogether, lol...
Perhaps an Exercise Kinesiologist is better, General Practitioners may not be in touch with the needs of those who use their bodies for much beyond the scope of office work, although it's certainly a good place to start...
Just make sure to get additional opinions if they want to go in and start cutting...
Best,
Michael
PS: Maybe ask JE (Justin Ehrlich) about it, as an Acupuncturist, he's familiar with herbal formulas.