Keeping your guitars in shape!

Bones

Could be a combination of humidity (probably low humidity) and truss rod (probably too tight). DO NOT mess with the truss rod unless you are sure that you know what you are doing as you can definitely do damage if you overdo it. Take it to a competent luthier if in doubt. BUT, if you are handy and motivated to figure it out yourself there are a lot of good vids, etc. out there. Be careful and don't practice on a valuable instrument.

If you live in a dry climate make sure that your guitar is stored in the hard case at all times when not being used and use a hygrometer and case humidifier to maintain the proper humidity. That may fix the bump where the body and neck join.

Back bow could be too much tension on the truss rod. You want a LITTLE bit of relief in the neck (up bow) to prevent buzzing.

asura

Thank you @Bones ! Humidity is pretty low here indeed. I use the oasis humidifier but probably better to keep it in the case as well :-)

Bones

Asura, try the humidifier for a week or several weeks and see how it settles out. Shoot for around 50% RH and 70 degrees F as best you can.

Jeff Moore

Asura
Wood is a kind of sponge. It takes on water and then dries out. If you take a new perfectly rectangular sponge and put it through a few soak and air dry cycles, it will never return to a rectangle. It'll cup. Like the wood in your guitar, the sponge is drying first on its edge and later the center eventually dries out. If you soak the sponge, wring it out hard, then let it dry, it'll dry quicker and more evenly and return closer (but not that close) to a rectangle.
The neck joint is a bigger collection of wood (bigger sponge) than the neck (small thin sponge). More wood = more swelling = longer drying cylce. So your neck dries out quicker and more completely that your neck block.
Once that bump has formed, it doesn't ever completely or even mostly go away, just like the sponge doesn't return to a rectangle. It's as if the neck block swelled and refuses to un-swell ever. Whereas the thinner neck shrinks more so there's your bump. Only sand paper is going to return the shape of the neck to a straight line.
There is no quick fix. A truss rod can't cure a bump, though it might make an improvement.
It needs a fret board re-leveling to get it to "perfect", but a less perfect but good enough remedy is to just level the frets. This will leave you with taller and shorter frets. So if the neck join bump isn't that big, a fret leveling will suffice. You might worry about having uneven frets that are never the less perfectly level to each other on their tops, but I don't notice it much.
In the long run there is no alternative but to control the moisture wherever the guitar lives to prevent wetting and drying cycles from occurring. It's tyrannical in that the guitar parent never gets time off. Only constant disciplining of the guitars environment will ensure good behavior. Even with perfect monitoring and control of moisture, time will still do things to wood. Life is hell.
I don't know how a guitarist can survive without being either wealthy (paying a tech to take care of the children) or becoming a guitar tech on your own, ready with sand paper, frets, and straight edge to discipline my necks.

asura

@jeffmoore Thank you for the well thought out explanation! :-)

That makes a lot of sense and I regret to have not been taking better care from the start. But better late than never! :-)

Thank you again for the detailed insight, I appreciate it a lot!