Yes. Yes. Straining during bicycling riding can cause upper and lower back pain. Usually caused by muscle straining.
Yes. Especially if hunching forward for a long time. Ribs get flexed downward in front and upper vertebrae bend forward. When you straighten up, one or more may stay 'stuck' in that forward-bent position. An osteopathic hands-on exam and treatment can frequently resolve the problem. If it keeps recurring, consider changing the chair or way your sit or consider prolotherapy.
Yes. Poor sitting posture, an inadequate chair design and long periods of sittibg can affect your back.
Yes. But its not a typical symptom.