Shoulder and lower back pain after squats

[Kerber]

Today I did squats at around 228 lbs. After the last set, I felt a big pain in my right shoulder as if it was strechted way too much. I guess it's the rotator cuff. I watched the video and noticed that my elbows seem to flare around on the way up. So I tried to keep my elbows a bit more down and what happend was...well it still hurt and I also hurt my lower back.

Here's the video:
https://www.youtube.com/watch?v=bsP-NpDruJI

I canceled the training session and went home. The shoulder pain was gone after about 20 minutes, it feels good now, but my lower back still hurts whenever I stand up I know that the video isn't the most detailed but can you maybe see what could have caused these problems since I really need to fix them.

[Tom Campitelli]

Big pains generally do not go away after 20 minutes.

Your squat doesn't look great, but it doesn't look particularly injurious, either. You lift your chest quite a bit during the middle of the ascent. This may cause you to overextend your back. Cannot really say from here. I can tell you that you need to contract all of your muscles harder and get tighter. Stay with your hips. Drive your butt up the whole way to the top. Don't try and bend the bar across your back. That can bother shoulders and elbows.

[Kerber]

I took one week off. Now I'm trying to get better form.

https://www.youtube.com/watch?v=D24NYH-IosI

It just does'nt look solid. Am I leaning forward too much? Is the stance to wide? Mobility issues mayb?

[Tom Campitelli]

Not too bad. First rep is on your toes, but the rest look okay. Really work on driving up with your hips. You still like to lift your chest. You have perfectly adequate mobility to squat.