Don't over exert yourself. Eat lot of proteins like cheese, soybean, tofu, porridge, sprouted black grams. Also instead of lifting weights first of all start doing push-ups and chin-ups to increase muscle strength.
Erasmus Mundus Master in Adapted Physical Activity, MPT, BPTh/BPT
Physiotherapist, Chennai
It is called as peri arthritis shoulder and for that you can do hot water fermentation and ice therapy at home. If you have shoulder pain then the stiffness will develop more that might make the arm to have less improvement which might make you to feel more pain the arm. And also cervical pillow can be used which might make you to have better posture of the shoulder neck and arm.