Hi,Dear,Thanks for your query to HCM.
Dear I read your query and reviewed it with context to your query facts.
I understood your health concerns and feel Concerned about them.
Based on the facts of your query, you seem to suffer from-
Post-
Vasectomy Tender Granuloma.The changed cicustances after vascectomy casuse partial congestion which resolves over time.Might be some unabsorbed portion seems to be got infected with subacute infection at the Granuloma site around the un-absorbed portion of the Vasectomy suturing thread.
The 
spermatic cord is very sensitive structure with nerves and vessels of testes and cause pain in the cord and if traction is caused to the cord or testes, it causes 
abdominal pain,because the sympathetci pain fibers also supply intra abdominal around  L-1,L-2  area from the testicular vessels get supplied from renal plexus which is part of celiac sympathetic ganglion and which also supplies abdominal viscera.Therefore any testicular or spermatic traction or pressure causes 
referred pain to abdomen.
As your pain is post 4 yrs of vasectomy, its definitely UNUSUAL,for you to have pain in the testicles.
The reasons are explained above already.
Remedy-
Conservative-
GEt USG study / or color doppler to study the 
venous congestion at the painful site and ,to study the extent of local damage at vasectomy.
Assess this report with 
Second opinion from Surgeon near your area.
Tab Dicloran A 1 x 2 times per day x 10 days 
Tab Chymoral fort 1 x 2 times per day x 10 days 
Tab Ciplox 1 x 2 times per day x 10 days.
Supports to  sensitive Scrotum- to reduce the 
testicular pain.
Surgical-Remedy-
If no relief in any -pain, Surgical Exploration to remove the Painful Granuloma at Vasectomy point is the final solution for  your case.
Hope this would help you to reduce worry with your problem.
Take care and wish you to recover fast and Live healthy.
Hope this reply would help you to plan further treatment with your family and specialist doctors there.
Welcome for any further query in this regard.
Good Day!!
Dr.Savaskar M.N.
Senior Surgical Specialist
M.S.Genl-CVTS