I decided to pick up the bass this week for the first time in years, been practicing about 4+ hours a day to get back into the swing of things.

Something Ive never done is 2 handed tapping. One of the ways in which Im acquiring this technique is through merely gaining the initial finger strength to make notes ring without plucking, through hammer ons with both my left and right fingers. (I have long skinny bitch fingers) I'll usually go up and down the neck with each hand hammering various chromatic patterns to a metronome, making sure I can get each note to ring.

Over the last 2 days, Ive started developing a pain in the pinkie of my fretting hand. It almost feels like the soreness in a muscle after going to the gym. Should I assume that is all the pain is and that my fingers are merely adapting to playing bass again? Or should I be genuinely concerned? Cant really say Ive ever used my pinkie for much on guitar or bass and im noticing myself getting stronger each day.

The other possibility I considered is that my bass is over 20 years old, was purchased from some guy on craigslist for $100 2 years ago, and has never been looked at by a tech. If the action or setup is fucky, is there a possibility that Im forcing my hand to work harder than it needs to? Ive picked up other cheap, shitty basses that were properly setup which played noticeably better than mine.

Wat do UG?
They don't sleep anymore on the beach..
You've probably just bruised your finger tips. I'm just recovering from some over enthusiastic hammering (!) it lasts a few days if you stop playing until it recovers but gets worse if you persist, I had a gig coming up and persisted but cut down to about an hours practice a day with no hammers and it's stating to get much less painful after three weeks. I couldn't type with that finger three weeks ago.

Your bass needs a set up, I check mine monthly and do it properly every time I change the strings. Adjust the truss rod and set the action and intonation, it's a five minute job with an electronic tuner (needed for the intonation unless you have a great ear) Might be worth getting it done professionally for the first time as the truss rod is likely to be sticky if it hasn't been adjusted for years.