@zain_haider1
Yes seems some solenoid related issue, Solenoid switches a large electric current ( in response to a small control current from your battery) to the starter motor which puts the engine in motion
Also check your battery from some good Battery shop
If solenoid receives insufficient power from the battery, it will fail to start the motor, and it will just produce rapid clicking sound.
The lack of power can be caused by:
1.Low battery(90% of the time this is reason)
2.corroded or loose connections in the battery cable
3.damaged positive (red) cable from the battery.
Any of these problems will result in small amount of current which would not having enough power being sent to the solenoid, which means that the solenoid will only begin to push the engagement gear, making the metallic click sound.
For example, Take some figures as assumptions:
It is so simple that if you give 10 mA to Solenoid it will magnify 10x (10 times) & makes it 100 mA to start main motor but if you will already give 5 milli-Ampere or 7 milli-Ampere the solenoid will be able to reproduce only 50 mA or 70 mA (10 times) which will not be able to start the motor
Also might be back current is coming fine i.e. 10 mA but solenoid switch itself is not able to amplify it 10 times 10x & might be able to give 6x or 7x .........again insufficient power to start motion
Solenoid will look like:

in which city u r? if in Khi then go to Mandviwalla for sorting this issue