Weight Painting ghost influence

Hi, I’m new to rigging.
Note: I’m using Rigify to generate the rig

After using Blender’s “set automatic weights” feature, I wanted adjust the weights so I jumped into Weight Painting mode. Then I stumbled upon two issues:

The first problem is that when I select the bone that is assigned to the vertex group that i want to weight paint, Blender does not automatically select that vertex group for me, so I have to manually scroll down the object data panel and select the desired vertex group, which is very tedious. Is there a special option for that?

Secondly, probably due to my inexperience with rigging, my upper arm bone is not deforming the mesh correctly. Its disregarding the weights I assigned to it, so when I edit the weights, there seemed to be no effect on the deforming of the mesh. Instead, when I edit other weights that are assigned to bones near the upper arm bone, it affected the deformation when I moved the upper arm bone.

Some pictures (the weights all belong to the vertex group assigned to the bone that is being moved)

View of armpit area when bone is moved: (The bone is deforming parts of the mesh that are not weighted to said bone.)

Same view of armpit area when bone is back to original position:

View of shoulder area: (even as I subtracted some of the weight regions that seem to be responsible for the ugly crease, the crease still remained)

(As a novice) I suspect my first and second problem are somehow co-related. Thanks for reading and/or helping! :spin:

I’d really need to see a blend file to make any guesses. Use pasteall.org to upload the blend and paste the link it gives you here.

Screenshots almost always leave out most relevant information. (That is the case here. I cannot see any of the topology, nor the bones and their properties, or the rigging, mesh information, etc,…)

Good luck!

Oh, sorry for checking back so late. I think I found a way around the issue (my dumb luck). I’m using Rigify and I was watching Kent Trammell’s tutorial here:

After he parented the mesh to the armature bones with automatic weights, he hides the layer that contains the armature bones themselves (the bones that are tinted green), so only the custom bone shapes are visible. Turns out that the weights are assigned to the armature bones, which are ultimately assigned to the custom bone, so Blender will only automatically select the vertex groups if the actual armature bones (that the vertex groups are assigned to) are selected

As for my second problem, it was due to my weights overlapping with one another

Thanks for your time, I really appreciate it!