Please help if possible. My girlfriend and I rode for 4 hours and the day after started experiencing neck/shoulder pinching and lower back pain. Is **** normal? Is she just "sore" from her first long ride?

Also, her position is pretty much upright with swept back handlebars. Could this position be stressful to those points?

Yeah bolt-upright is hard on the back. Here's a good page to poke around:

https://www.sheldonbrown.com/pain.html

How often/long have the both of you ridden before?

I've ridden but not her. But since this is her first time, should she have this kind of pain? Would she get used to it?

Have she been properly fitted for her bike? Improper fitting can cause some tension on variable muscles during and after riding which can result in some injuries if you are not careful.

As far as fitting goes the saddle is the height so that her leg is bent at the knee slightly when the pedal is all the way down and the handlebar is raised to her liking.

Someone who doesn't ride, who suddenly rides 4 hours ... YES will be in a ton of pain, not just in the legs.

When I got back on the bike after a few years off, my first 5 mile commute had me in pain - can't imagine how I would have done four hours. And while I have no problem riding 8-10 hours a day with my drop bars, I would hate to ride more than a few miles in that upright position.

Mosquito

A good way to figure out if the seat is at the right height is to ride behnd her and watch her hips. If the saddle is at the right height, the hips won't move much with the pedal stroke, if the saddle is too low then her left hip will be lower than the right when the left foot is at the bottom of the stroke, if the saddle is too high, then it is the other way around. with the left hip dropping as the left foot reaches the bottom.

Strongly recommend visiting a bike shop to have a good fitting done, proper bike fit has more impact on the comfort of the bike than most anything else.

Exactly, it's like deciding to run a mile straight when you haven't exercised in a few years.

There are two things going on. First, any new activity is going to stress the body more than something it's used to. I've seen weight lifters think they're going kayaking for six or seven hours, only to come back after twenty minutes, unable to move their arms.

Second, and more importantly, her bike isn't set up right for her. It sounds like you got the saddle height right. What about its position front to back? Are the bars the right height? The right distance away? Bike fitting is a complicated art. Try the Sheldon Brown link for starters. If that doesn't work, post some photos here and people will critique her fit and posture.

Did she have any pains while riding the 4 hours, or just started having some the day after? I like the other posters suggestions about getting her fitted by the LBS, or by taking pictures and posting them here.

I will also echo others sentiments that riding 4 hours at one time and not riding previously will produce some pain.

Also, what is the extent of the pain? Is she pretty much bedridden or can she get by with just some advil and just complains about her neck and back?

This is the biggest contributor to her soreness. There may be fit issues as well, but 4 hours as her first ride is going to cause soreness.

Yep, neck and shoulder and back, gets by with advil. I will let her wait a few days and see if it goes away. Then hop back on again to see if the same pains occur.

get her a big bouquet of flowers, take her out for a nice dinner! your girlfriend was a real trooper to go the 4 hour ride with you. the fact that she didn't complain after the first little bit, she probably started having felt some discomfort during the ride - she is one tough gal - and you are one lucky guy not to have a whiner on your hands! so do her right and let her know how special she is!

Since the pain is not debilitating then she should be fine after a few days. Its possible the bike fits fine and that all that's wrong is she is not used to riding. Maybe treat her to a sports massage or something.

When I first started riding regularly, I had a lot of shoulder, neck, and elbow pain. After a few months it went away. On the other hand, a bad fit can cause that kind of thing and it will never go away.