Is it possibe the severe pain in my hand could be from a degenerated joint condition, or could my ganglion cyst be growing inside and not so much out?

Not likely ganglion: Ganglion cysts do not usually produce severe pain unless they are pushing on nerves. It is likely from another cause.

Possible: Hand pain can be caused by many different things. If you are having pain at the base of your thumb it is likely basal joint arthrits which is an arthritis of the base of the thumb. Initial treatment involves a custom molded splint and over-the-counter anti-inflammatories. If the symptoms don't resolve you can consider an injection of cortisone. I would see a hand surgeon for definitive treatment.

Uncertain: If pain is fom ganglion then usually you would have evidence of a visible cyst.

Either is possible.: Severe hand pain can be secondary to a variety of conditions. Degenerative arthritis will certainly cause discomfort in the affected areas. Wrist pain could be caused by arthritis. It can also be caused by a ganglion cyst that is not outwardly obvious--a so-called occult cyst. An MRI is helpful to make the diagnosis in these situations.