Vitamin B12 level 795. Very concerned!

I am 57 years old male. I am recently having pain near left triceps and 2 kgs of weight loss in last 2 months. The tricep pain started earlier but it worsened in the last 2 months. Doctor gave Neurobion Forte twice daily and prescribed several tests. Cardiac tests (echo and ECG) are normal, chest X ray normal, left hand X ray detected cervical spondylosis. Now I also did several blood test-CBC, thyroid, lipid profile, blood sugar, creatinine, potassium, sodium. Everything is normal except Vitamin B12 level. The range level of the lab was 190 to 840. My test result was 795. I think my level is very high in my opinion. I searched internet and saw that high b12 is sometimes related to leukemia and liver disease. I again say the CBC is completely normal . I am very concerned regarding recent 2 kg weight loss and this high b12. I am always a slim person. What is causing this high b12? I took Neurobion Forte only for 3 weeks before the b12 test.