My shoulder is hurting . i think i hurt it by lifting a child up at work . what should i do about it ?

Try to do some: stretching exercises for the shoulder and upper arm muscles (biceps/ deltoid/ trapezius) as well as topical balm or ointment to your shoulder along with massage. If this does not work, you may need to see a healthcare provider for muscle inflammation and relaxing medications. Sounds like you strained your shoulder muscle or tendon by picking up heavy object repetitively.

Unclear pain: Unfortunately, that is too little information to go on. The pain could be from muscle, ligament, tendon, bone or joint. More precise localization within the shoulder and what makes it better and worse would help with the diagnosis.