Hello i just read your query about your mother.Since you have not specified more about your mother's pain quality ,exact site of pain i.e joints etc,the name of the drug for blood pressure that she takes and the aggravating and relieving factors associated with her pain i can't pinpoint exactly as what is going on with her so i will just put up a generalised solution.
1-Take time to get out of the bed. Wait for 5-10 minutes before she gets out of the bed.
2-Try to do all the heavy work of routine life if needed before going to bed.
3-Try to do stretching exercise like
yoga before going off to bed.
5-Try taking warm shower after waking up from sleep for 10-15 minutes.
6-Try to change the mattress if that is not comfortable enough.
7-Try massages.
8-Try to get the sunshine vitamin D.
9-Try to increase milk and milk product intake preferably low fat cansidering her Blood pressure.
10-last but not the least is that try to let me know the blood pressure medicine as that could possibly cause pain too as some drugs do have long term side effects.
Hope this helps solve your query.