Noise in the circuits, a ground problem?

[Lee]

This phenomenon happened in a few builds:

After I soldered the circuit and plugged in my bass guitar, it was quiet when I connected it to the battery.

Then the moment I touched the strings, the noise appeared as if I turned on a high-gain distortion without any noise reduction.

I played E string while putting my fingers on the A string, and the noise still occurred along with the E note.

As long as I left my fingers out of the strings or the ground spot on the circuit ('cause when I put my finger on the ground spot, there was the same noise too), the noise was gone.

My bass guitar worked fine as I tried several other pedals and there was no noise as mentioned above. This problem happened in some of my fuzz pedals too, such as the devi ever Electric Brown fuzz and the orange squeezer compressor.

Any suggestions where I may have done wrong?

Thank you!