Mri of shoulder mild partial intrasubstance tearing of supra, infras and subsc tendon insertions". Tendinopathy of the intra-articular bicep tendon?

Diagnosis? Don't make the mistake of determining your treatment based on an MRI reading. If you don't already have a diagnosis that makes sense to you on an anatomic basis prior to the mri, consider a second opinion. For instance, the number of changes you describe may be because of chronic untreated instability. Learn more: http://theshouldercenter.Com/shoulder-pain.Htm.
Rotator cuff. The supraspinatus, infraspinatus and subscapularis tendons are components of the rotator cuff. The tears are within the tendons but do not involve the inner (articular) or outer (bursal) surface of the tendons. This is less severe than a full thickness tear. Part of your biceps tendon is inflamed. You should follow up with your doc regarding pain management and possible physical therapy.
Typical. This is typical in your age group. By age 50, the large majority of men (especially athletes) with have some degree of rotator cuff injury. My orthopedic colleague once told me, "if you're 35, and not pitching in the big leagues, then just live with it." obviously that's very general, but rest and physical therapy to strengthen the shoulder should suffice and surgery may not be needed.