If you experiencing side effects of the covid - 19 vaccine does it means, the vaccine is working?

Side effects or not, it's still working.

Yes. Most people will likely either experience no side effects or only mild ones like headaches or soreness around the area you got the shot from. 

I would certainly think so.  Side effects are your immune system's response to the vaccine.  But it will still work if you don't have side effects.  

As with any vaccine, an immune response can be a positive indication that your body has reacted to the attenuated virus. The response is essentially your body learning (by producing antibodies which remain for around 6-12 months) how to protect itself against that virus in the future. 

It's not a side effect, it is the intended response to a degree. 

 Yes it does; not everyone  feels effects.

Side effects?  That doesnt sound good, what side effects?