Could this be arthritis or carpal tunnel syndrome if I only have pain when typing?

Could be either. Carpal tunnel can be associated with aching pain in the wrist and fingers and/or numbness and tingling usually in the thumb, index and middle finger. The symptoms usually are more noticeable when the wrist is either cocked up, say when driving or bent under when our hand and wrist are under a pillow while sleeping. Nerve conduction tests are very reliable in making this diagnosis.
They both could. Carpal tunnel syndrome which occurs in the hands after repetitive activities of the hands can cause pain but numbness and tingling are usually more prominent in the 1st 4 fingers of either hand and can wake you up at night. Arthritis can also cause pain you are describing and would be more likely if swelling, redness or warmth is present. Overuse syndromes can cause similar pain. Rest the hand.
Difficult to say. This would be difficult to say. Normally, carpal tunnel syndrome is associated with numbness in the fingers more than pain. Arthritis can develop in the hand and could cause pain when typing, however, at your age, I would say that arthritis is unlikely. My best advice would be to see a health care professional to help establish a diagnosis.
It could be either. Carpal tunnel usually causes pain and numbness in a certain area of the hand. It can present with just pain. Arthritis should only cause pain. Furthermore, other conditions can cause pain with typing, eg tendinitis. The bottom line, go to your doctor to get it checked out if it is bothering you or limiting your recreational or occupational activities.

Related Questions

How wouldes typing and texting cause carpal tunnel syndrome?

Repetition. Repetitive flexion and extension of the wrist might produce a localized inflammation termed a synovitis, which can narrow the carpal tunnel beneath the transverse carpal ligament.
Probably do not. Most people that develop carpal tunnel syndrome do not have a clear cause. There is no science to show that it comes form overuse or typing. It is more likely in patients that suffer from diabetes or hypothyroidism or obesity. It is also more common in women than men. Flexing the wrist while typing may aggravate the problem by increasing the pressure in the wrist around the nerve.

I'm experiencing a few symptoms of carpal tunnel syndrome what can I do now other than stop typing?

Wrist brace. If you wear a wrist brace to prevent flexion of the wrist, or get steroid injection close to the carpal tunnel, you can feel better==- if no help, as for surgery if carpal tunnel confirmed by nerve test.
Bracing can help. First, I would recommend an evaluation by a health care professional. There are a number of other diagnoses that can be confused with carpal tunnel syndrome. Assuming that the diagnosis is established as carpal tunnel syndrome, a good initial treatment would be bracing at night and during the day when you are experiencing symptoms. Many stores and pharmacies carry carpal tunnel splints.
Splint. Rest, night splint, vitamin b6 100mg / day, over the counter anti-inflammatory meds and ergonomic changes to work space.