Squats can cause back pain, both in the upper, middle or lower part. Most common is lower back pain and it is usually a result of improper squatting techniques, such as loss of neutral curve of the spine during the squat movement. Other factors that may provoke back pain during squats are bar position, reduced mobility and/or stability in joints, inadequate breathing technique. 

Lower back pain after running is often a result of loss of pelvic control, weak core and leg muscles, overtraining or improper shoes wear. That causes muscle strains in the lower back and increase muscle soreness. Pain itself can be annoying and last few weeks. Pain exists in the lower back, mostly on one side.

One of the most common injuries in the back after deadlifts is muscle-related injury and includes muscle soreness. Researching more about deadlift and back pain I found the following answer. Back pain after deadlifts often happens because of poor muscle activation/technique or overloading.

The joint by joint approach is a unique way to analyze the functional needs of our joints. The author of this method is physical therapist Gray Cook. Click to read the full text.

Improving the function of the joint and increasing the range of motion is the goal of the active range of motion exercises. Those exercises help you move better and they improve joint health overall.

The range of motion refers to the amount of joint's ability to move in any direction to its limits. It depends on various factors such as joint structure, function, ligaments and muscles.

The main rotator cuff muscles function is to stabilize, protect and control the shoulder joint during the arm movement. They provide dynamic stabilization to the shoulder joint and are involved in every activity which involves arm moving.