Why is my fan behaving this way?

So,I turn on my Macbook I boot into windows and launch my game... But I have extremely low fps and this has never happened before, so I update drivers and do other things in an attempt to fix my fps... After several hours, I figure out that the left fan isn t working. So I do some searching and find a "solution" that doesn t involve opening my Macbook since I have no knowledge of what to do. The solution was to bang on the bottom of my Macbook gently on the left side. And it did work, the fan started working and I confirmed that by downloading a fan control software. But after 20-30 mins it stopped working again and I had to do that solution again. I don t want to do that anymore cause it must be negatively affecting my Macbook and I want to know what s going on.

TL:Dr my Macbook fan isn t working (left) I bang on it it works but after 30mins it stops again what s happening please?

One more thing, the fan sometimes works and sometimes it doesnt. When it doesn't work it's on 0RPM