Thanks for the query to H.C.M. Forum.
Lump , in the neck may be enlarged lymph node
( lymphadinitis , that's why there is pain).
Now pain in the shoulder joint with stiffness
It is impossible to say , what is the reason as without X ray reports and blood reports.
So please upload these reports.
May be bursitis, osteoarthritis
rheumatic pain. osteoporosis
Consult an Orthopaedician / physician and get treatment .