extreme pump, burning feeling in lower legs when walking

Since quite some time I experience a burning feeling, like an extreme pump, in my lower legs when I go for a walk. It’s not in my calves but rather the front/side (tibialis anterior?).
It starts after about 10 minutes, when I walk at a brisk pace (RPE6 - 6.5). It’s so bad I have to stop walking quite frequently. I tried just ignoring it and keep walking but after some time it’s just hard to lift my foot from the ground. (not able to roll my foot anymore)
I hoped it would get better with incorporating these brisk walks during GPP, but it hasn’t improved at all.

I go for 10-15 minute walks about every day. (lunch break) These walks are maybe a bit slower but not too much.
No real issues there.
I try to get off my seat about every hour at work, and walk around for a few minutes.

What could be the cause?
Any advise for treatment?

How old are you? Any medical history?

I’d recommend a physician evaluation for this.

I’m 42.
Medical history: Sarcoidosis (lungs), sleep apnea

I’ve been to a few physicians already.
They had no idea what the cause could be. But I’m willing to give it an other try.

rho, what did you find out about this? I’m having the same issues.

I don’t have this issue any longer.
I just started walking slower. Reduce pace to a slow walk. And build up from there.
The fist week this can be annoyingly slow. (too slow to be exercise/significantly raise your heartbeat)
Hope this also helps for you.