I have arthritis which causes serious pain on both my knees my doctor suggested to lose weight should i do cycling?will it make my pain worst? age 45

Yes/no: Cycling is better than running if you have knee pain since it puts less stress and shock to the knees. However, you may still have some pain from use of the joint. That is fine as long as it is tolerable so that you can do effective exercise. But you can also do yoga, tai chi, swimming, etc. Any is fine.

Yes: achieve normal weight is the best thing to do to minimize symptoms of arthritis. swimming and non-impact activity is best