Lefty50:

Knuckle pain can be the result of one (or several) factors. They include:

1. Improper span:  In my experience, knuckle pain can actually be the result of
    too short of a span. Over time, the webbing located at the base of the thumb
    (between the thumb and index finger) will often stretch, causing the span to
    increase. Too short of a span will often cause pain in the finger joint, especially the
    middle joint.

2. Excessive reverse finger pitch ( towards the palm). This will often cause the fingers
    to hyper-extend at release, putting pressure in the finger joint.

3. Finger inserts too snug. Believe it or not, this is a culprit that is often overlooked.
    This is a major source of finger joint pain because it will also cause your fingers to
    hyper-extend upon release. One small test you can do is to grasp the finger that is
    giving you discomfort and gently pull on it outward. If you feel pain in the joints,
     you can bet your discomfort is due to finger hyper-extension.     

4. Excessive grip pressure (but not often a main cause).  Make sure your span and
    pitches allow you to swing (and release) the ball with MINIMAL grip pressure.

5. Age. Age. Age. ( I should know).  As I got older, it became increasingly important
    for me to be much more aware of all of the above factors.  I miss the days when
    I could get to the bowling center, shoe up, and simply grab a ball and hit "go". Not
    anymore. Nowadays, I virtually need a checklist of things I need to do before even
    leaving my house. Do I have my glasses with me? Do I have my knee braces? Did
    I remember to take my ibuprofen at breakfast?  And once I get to the center, I pay
    special attention as to how the ball feels in my hand before even throwing it for
    first time. Can I hold it and swing it without the use of a lot of grip pressure?

In the end, isolating the cause of finger joint pain is a process. There can be other factors that are giving rise to your discomfort that are not mentioned above. However, the ones I listed above are a good place to start.

 I wish you the best of luck!

Thanks to both. I caught the pitch issue, but definitely understand the point. Moving back to relaxed grip though, is it physically possible using a relaxed grip to put pressure in between the first and  second knuckle to relieve the joint while/if/until/hopefully heals? I have a knot on top of the knuckle that has already forced me to change from a 49/64 to a 53/64 just to come close to fitting the finger in the grip....

I have knots on both of my bowling fingers. I struggled for years with finger swelling where the knots were.  During the second half of last season for whatever reason I was having a difficult time controlling the breakpoint with anything--and because of that I ended up converting to conventional grip(with inserts)...for me I still get plenty of movement on my shots, but not like before, which is the main reason I made the change, but one thing that has happened is that I do not get any swelling anymore in my fingers at all....One thing that I found out a couple of months ago is that I have arthritis in my bowling hand, and I have bone spurs on my fingers(where the knots are)---which explains why a few years past I used to feel stiff in my fingers before bowling, not realizing that I had arthritis in my bowling hand. Anyways for me going conventional with inserts helped my controllability on the lanes and my finger swelling issues.

Brad

I've seen SteelFingers advertised, but sure looks gimmicky. You're the first I've heard that had luck with them. The pain in my first joint is just above where the Steelfingers starts, so I'm thinking it wouldn't help in this case.... but if it gets worse, I'll be open to anything. Went to a second pro shop and grip looks 1/4 inch long in that finger, so I'm having it plugged now. Fairly drastic changes. 1/4 inch shorter, 1/8 more reverse and increase grip size to accommodate the bump on top.
We'll see.