I had pain in my shoulder for a few months & it hurt to reach up or out. now extreme pain in bicep with a lump across my upper arm. what could it be?

Tendon rupture?: Should see your dr / urgent care / orthopedist soon for exam, possibly MRI and likely treatment. Sounds like you may have ruptured one of the bicep tendons.

Bicep painwith lump: There are many causes of shoulder pain: tendonitis, bursitis, sprain or even tear of the rotator cuff/the ligament/muscles which hold hand together. These when inflammed reduce your ability to raise your shoulder/arm. A lump usually suggest either a torn muscle, a bicep ligament tear, a cyst, ect. You need a physical exam and an MRI of the shoulder.

Let try to help: If that lump is recent? Do you have bruise in the arm? If you do? Most likely rupture of the biceps tendon around the shoulder.

Have it looked at: Agree with other docs. Pretty young for a cuff tear without trauma. Could be a proximal bicep rupture or even strain. Mri is helpful but if trying to avoid alot of cost may consider seeking a specialist trained with msk ultrasound which is signficantly cheaper than an mri.